How-To Geek

The Best Free Dictionary and Thesaurus Programs and Websites


Are you a writer? Or a word geek? If you write anything or play word games, dictionaries, thesauruses, and other reference tools can come in handy. We’ve found some useful offline and online tools for looking up words, finding synonym, or building words in Scrabble.

Dictionary and thesaurus programs and websites allow us to go beyond the dated, printed dictionary. You can find so much more up-to-date information on the web without having to buy dictionaries and other reference books. The following programs and websites provide useful reference tools for free.

Offline Desktop Software

The following software programs are offline programs you download and install on your computer. Some of the downloads may be large because the programs include the full dictionaries with the program for offline use.

Ultimate Dictionary

Ultimate Dictionary is a free dictionary program for Windows that is easy to install and use. It contains a collection of around 61 dictionaries, which includes dictionaries, thesauruses, and glossaries, as well as English, Spanish, French, and Polish word references.

When you type a word into the search box Ultimate Dictionary, it looks for it in all the dictionaries it contains at once and provides a meaning from each dictionary in which the word was found in the right pane. The results start to display as you type the word with hints provided for matching words. Quickly jump from one information source to another (translations, encyclopedia entries, glossaries) simply by clicking the Jump to Dictionary button and selecting a reference source from the list on the left.



WordWeb is a free dictionary program for Windows that provides a dictionary and a thesaurus. Each word is accompanied by synonyms, and where available antonyms (a word having a meaning opposite to that of another word), meronyms (a word that names a part of a larger whole; for example, “finger” is a meronym of “hand”), hypernyms (a word that is more generic than a given word; for example, “car” or “airplane” are hypernyms for more precise terms like Toyota Camry or Boeing 747), holonyms (a word that names the whole of which a given word is a part; for example, “hat” is a holonym for “brim” and “crown”).

WordWeb provides a keyboard shortcut that allows you to look up any word anywhere on your computer. By default, the keyboard shortcut is Ctrl + Right Click, but this can be changed in the Preferences. WordWeb also has access to online references that include Wikipedia, Wiktionary, and WordWeb Online, allowing you to access word definitions on the internet.

You can also access a history or your word searches, copy the results of a lookup, and click on any word displayed in WordWeb to display a definition of that word.

WordWeb is free, but they have a very unique licensing policy that you must satisfy to continue using the free program. Otherwise, you must purchase WordWeb Pro, which includes 5000 more definitions and many extra features.


TheSage English Dictionary and Thesaurus

TheSage is a free offline dictionary and thesaurus that contains a large dictionary of more than 210,000 definitions, as well as a complete thesaurus providing over 1,400,000 relationships between definitions, including synonyms, antonyms, hyponyms, hypernyms, meronyms, holonyms, and more.

TheSage has a tabbed interface, allowing you to look up multiple words at the same time. You can also search using wildcards and refer to a history of your searched words. The program also integrates into the Windows context menus, providing quick access to definitions from almost anywhere on your computer.

Other features include access to online references such as Wikipedia and Google (for definitions and translation), an anagram search, real-time search, system tray integration, and the ability to run TheSage from a USB flash drive.



LingoPad is a free offline dictionary for Windows that contains a German-English dictionary, as well as other dictionaries that are available for download. You can import your own dictionaries, define your own, and create and edit word lists.

The search feature allows you to search for the beginning, ending, or middle part of a word, search for collocations, and view a list of the latest search words. You can also use a hotkey to search for a tagged word or a word from the clipboard. There are direct links to look up words on Wikipedia and various search engines.

NOTE: Currently, LingoPad is only available for Windows, but there will be no further development of LingoPad only for Windows in the near future. However, they are planning to develop a cross-platform version of LingoPad for Windows, Linux, and Mac OS X.


Artha Dictionary

Artha is a free, cross-platform (Windows and Linux), offline English Thesaurus based on WordNet, which is a large, lexical database of English developed at Princeton University. For each word you look up, the possible relatives displayed by Artha include Synonyms, Antonyms, Derivatives, Pertainyms (related noun/verb), Attributes, Similar Terms, Domain Terms, Entails (what a verb entails doing), Causes (what a verb causes to), Hypernyms (is a kind of), Hyponyms (kinds), Holonyms (is a part of) and Meronyms (parts). Each of these links takes you to a definition and example of the relative category. When you select a relative in Artha, its corresponding definition is scrolled to and highlighted for easy understanding.

Artha starts searching as you start typing, displaying a list of possible matches from what you have typed so far. If you misspell a search word, Artha provides near-match suggestions.

Once you launch Artha, it sits in the system tray. You can look up words from any open window by selecting the text and pressing a pre-set hotkey. When using the hotkey, you can choose to have Artha show a passive notification, or balloon tip, so you can quickly continue what you were doing.

Artha maintains a history of all your search terms and provides Previous and Next buttons so you can easily browse through your searches.


Aard Dictionary

Aard Dictionary is a free offline dictionary and thesaurus program that allows you to look up meanings for difficult words using multiple dictionaries in multiple languages. You can add more than 50 different dictionaries to its database. Some of its features include on-the-fly searching and filtering capabilities, the ability to view a history or recent searches, the ability to zoom in and out of contents, and fast word lookups.

For words found on Wikipedia using Aard Dictionary, the full article is displayed and you can save the Wikipedia article as an HTML document on your local hard disk. Aard Dictionary also provides many keyboard shortcuts for those of you who prefer using the keyboard over the mouse for navigation.



GoldenDict is a free, feature-rich offline dictionary program for Windows and Linux. It supports multiple dictionary formats, such as Babylon, StarDict, and WordNet. You can also look up words on Wikipedia, Wiktionary, or any other MediaWiki-based websites using GoldenDict. It also supports looking up and listening to pronunciations using the pronunciation guide,

You can lookup words selected in other applications or translate a word from the clipboard using hotkeys.



Lingoes is a free, easy-to-use dictionary and text translation program that offers lookup dictionaries, full text translation and pronunciation of words in over 80 languages. You can also select text in other programs and windows and use a key combination to have Lingoes to display results for the selected text.

Lingoes provides free dictionaries, thesauruses, and encyclopedias for download and allows you to configure them yourself. In addition to using offline dictionaries, you can also use online dictionary services and encyclopedias such as Wikipedia. Lingoes also includes tools and references, such as a currency converter, international dialing codes, international time zone converter, weights and measures, and more. You can download additional tools, information, games, and shortcuts.


Mobysaurus Thesaurus

Mobysaurus Thesaurus is a free, offline, English thesaurus program that contains 30,260 roots and more than 2.5 million synonyms. It suggests results as you type, stores your look up history, and allows you to bookmark your favorite words and phrases. You can also perform a wildcard word search, search online for results, print your results, and copy your results to the clipboard.

Mobysaurus Thesaurus is freeware, but they ask you to register for a license key. It doesn’t cost anything. Register on their forum to receive a license key that is good for six months. After that, you need to go back to their site to get a new license key for another six months. One year after your initial signup, you can go back to the site and get a permanent, non-expiring license key.

Mobysaurus Thesaurus requires at least .NET Framework 2.0 to run.

NOTE: You can also download Mobysaurus Thesaurus from, but you still need to register on’s site for a license key.



CleverKeys is a free tool that allows you to access definitions at, synonyms at, facts at, and more from just about any Windows or Mac OS X program, such word processors, web browsers, and email programs.

Some features of CleverKeys include the ability to add your own URLs, highly configurable hotkeys, and the ability to open CleverKeys results in a new window. CleverKeys works with most current web browsers, including Firefox, Chrome, and Internet Explorer.



The following websites provide online dictionaries and other reference material. is a free, online dictionary that is part of the website (with, as well) and is an interactive and reliable source for word meaning and usage. With 50 million users around the world accessing the site every month, It’s the largest and most authoritative free online dictionary and mobile reference resource. can also be used on mobile platforms, including Android, iPhone, iPad, BlackBerry, Windows Phone, Nook, and Kindle Fire.


The Free Dictionary is the world’s most comprehensive, free, online dictionary with dictionaries available in many languages and other types of dictionaries available, such as Medical, Legal, and Financial dictionaries. It’s also contains a Thesaurus, Acronyms and Abbreviations, Idioms, Encyclopedia, a Literature Reference Library, and a search engine.

You can also make The Free Dictionary your own home page and customize it by adding and removing, dragging and dropping, and “using or losing” existing content windows. You can also add your own bookmarks, weather information, horoscope, and RSS feeds from anywhere on the internet.

You can access definitions on The Free Dictionary from almost any application on your PC by installing the free Desktop Assistant for Windows. Then, simply highlight a word, press Alt and left click your mouse, and the definition displays.

You can also install add-ons in Firefox, Chrome, Internet Explorer, and Safari that make access to The Free Dictionary quick and easy from almost any other webpage.



Wiktionary is a free, multilingual dictionary that is the lexical companion to Wikipedia. It includes a thesaurus, a rhyme guide, phrase books, language statistics and extensive appendices, as well as extra, clarifying information in the definitions, such as etymologies, pronunciations, sample quotations, synonyms, antonyms and translations.

Wiktionary is a wiki, so you can edit it. However, before you contribute, be sure to read through some of the Help pages, as Wiktionary does things differently than other wikis and they have some strict criteria.


Merriam-Webster Online Dictionary

The Merriam-Webster Online Dictionary is a free dictionary based on the print version of Merriam-Webster’s Collegiate® Dictionary, Eleventh Edition. The online dictionary includes the main A-Z listing of the Collegiate Dictionary, as well as the Abbreviations, Foreign Words and Phrases, Biographical Names, and Geographical Names sections of that book.


Oxford Dictionaries Online

Oxford Dictionaries Online is a free website that offers a comprehensive, current English dictionary, information to help you write better, puzzles and games, and a language blog. It also contains up-to date bilingual dictionaries in French, German, Italian, and Spanish.

They also offer a premium site, Oxford Dictionaries Pro (£42 per year), which features more than 350,000 definitions, 600,000 synonyms and antonyms, and over 1.9 million usage examples, all linked intelligently and seamlessly, audio pronunciations, example sentences, advanced search functionality, a puzzle solver section, and specialist language resources for writers and editors.


Collins Dictionary

The official online Collins Dictionary contains over 1 million entries, and provides free access to word definitions, translations, and examples. There is also a section where you can play word games, such as crossword puzzles and cryptic crossword puzzles, use their Scrabble Checker, and learn from their top 10 Crossword Tips and top 10 scrabble tips.

They also provide a widget that allows you to place the Collins English Dictionary, French Dictionary, Spanish Dictionary, German Dictionary or Italian Dictionary on your website or blog.


Word-Net Online

Word-Net Online is a free, English dictionary and thesaurus that offers definitions, synonyms, antonyms, hypernyms, hyponyms, meronyms, holonyms, derived forms and sample sentences.


They also offer a free dictionary and thesaurus program for your Windows desktop. Install the program and search for any word or term on WordNet-Online directly from your desktop.



OneLook is a free dictionary site that can be thought of as a search engine for words and phrases. When you look up a word on OneLook, you are directed to the web-based dictionaries that define or translate that word. The OneLook search engine indexes more than five million words in more than 1000 online dictionaries.

You can also use OneLook to find a word when you only have part of it, similar to a crossword dictionary. Enter a pattern using letters and the wildcards * and ? to display a list of words matching your pattern. If you enter a word and select Find translations, OneLook displays a list of dictionary websites that have translations of that word into other languages.

OneLook can be customized to the way you work, as well.


OneLook also has an interesting feature called a Reverse Dictionary. This allows you to describe a concept and receive a list of words and phrases related to that concept. You can enter a few words, a sentence, a question, or even one word. The best results are obtained if you keep the entered phrase short and the best matches are shown first in the list of results.


Urban Dictionary

Urban Dictionary is a web-based dictionary of slang words and phrases written and rated by site visitors (voted thumbs “up” or “down”) and regulated by volunteer editors. As of September 6, 2012, it contained 6,743,306 definitions. Visitors to Urban Dictionary may submit definitions without registering, but they must provide a valid email address. All new definitions must be approved by the editors. Once approved, entries become the property of Urban Dictionary.

The definitions on Urban Dictionary are meant to be slang or ethnic culture words, phrases, and other terms not found in standard dictionaries. Most words have multiple definitions and include usage examples.


MetaGlossary is a comprehensive, highly organized dictionary and glossary. It’s the world’s largest, constantly-updated repository of information, harvesting definitions from the entire web. MetaGlossary precisely extracts the meanings of the terms and phrases it finds on the web and provides you with concise, direct explanations for the terms and phrases. The meanings are also organized based on topic and usage.


Specialty Dictionary Programs and Websites

In our search for useful offline and online dictionaries, thesauruses, and other reference tools, we also came across some dictionary programs and websites that serve special purposes, such as a dictionary only defining computer terms, a crossword dictionary, and a few Scrabble dictionaries and word finders.

Smadi Computer Dictionary

The Computer dictionary is reference tool with a very simple interface, in which you can find over 86,000 computer and technology related acronyms and their definitions.



Crossinary is a dictionary program for Windows that helps you create and solve crosswords and other word puzzles. It contains over a quarter of a million English words (including some proper nouns) and allows you to quickly search the massive list to find all the words that match a pattern, such as g-something-something-k.


Free Scrabble Dictionary

The Free Scrabble Dictionary is a free tool to help you look up definitions and find words to use when playing Scrabble. They have tens of thousands of words and a half a million definitions. You can also use the Free Scrabble Dictionary to play other word games, such as Words with Friends, Scramble with Friends, and Hanging with Friends.


You can also use the Hasbro Scrabble Dictionary and Word Builder and the Word Finder websites to help you play word games, such as Scrabble®, Lexulous, Wordscraper, Scrabulous, Anagrammer, Literati, Text Twist, Jumble Words and Words with Friends.


If you’ve found any useful dictionary, thesaurus, or reference resources or other dictionaries and tools for playing word games, that are not on this list, let us know.

Lori Kaufman is a writer who likes to write geeky how-to articles to help make people's lives easier through the use of technology. She loves watching and reading mysteries and is an avid Doctor Who fan.

  • Published 12/22/12

Comments (20)

  1. ReadandShare

    Lori — thanks a lot for overwhelming me with choices! (smile)

  2. C1pTr

    Good article, but I think that is good to mention, too

  3. WandersFar

    Wolfram Alpha is also great for finding words that start, end, or contain certain letters. It also has dictionary, thesaurus, frequency, etymology and translation functions.

  4. mohammad

    How come you forgot to mention Google’s dictionary tool? :)

  5. Lucian
  6. CutTheRedWire

    I keep a vocabulary file for obvious reason. In it, I always use Merriam-Webster links. You can shorten the domain name of any link from “” to “” which saves space.

  7. Mohammad Mazahir

    Wow thanks Lori Kaufam for this nice article.It was really helful especially for geeks like me hahah just kiddin.The very best thing of these dictionaries is that we can use it offline i mean without internet.
    I have download wordweb.

  8. Joshua

    Great list, However Can anyone tell me where to find technical dictionaries & translations?
    with words like ball bearing – kogellager, crankshaft – krukas.

  9. Anji is also the one

  10. cam2644

    I’ve been using for some time and with no complaints

  11. StevenTorrey

    In today’s trivia question, a debate arose over use of ‘rein’ vs ‘reign.’ A thesaurus or dictionary will not pick up grammatical usage or mis-usage, will not pick up homonyms misused… Simply put those rules are learned in grammar school. When I was a grammar school student–I’m 67 now–I don’t remember having trouble learning to spell–correct spelling seemed to come naturally. My guess is that a young child sees the spelling of the word like a picture would be seen–so the student does not have to learn to spell the word by deciphering each individual letter; rather, the picture of the word’s spelling. Course, not being dyslexic helps…

  12. Beverly

    I been using wordweb forever it seems. Great little program. On the other hand, I had no idea there so many choices out there. Thanks.

  13. john3347

    I have been using WordWeb for a few years and Although it is very easy to use to check both spelling and meanings of words, it is quite short on content. I frequently cannot find the meaning of whatever word some geek writer throws out into the world.

  14. Perry

    Thanks for the comprehensive list. BTW, I’m surprised a writer would say ‘very unique’!

  15. Jason

    There is such a thing as a bad dictionary, and many of the online options qualify. Anything is fine if you just need a reminder about correct spelling or stumble across a new word in a novel, but if you’re interested in deep definitions and shades of meaning, you should use an authoritative dictionary that employs lexicographers.

  16. Dic

    What a great selection! Thanks Lori Kaufam. But to save my having to trawl through the list to find one that doesn’t make use of Noah Websters fiddlings, can anyone point me to one for British Isles English, or even New Zealand British English?

    @Perry: Surprising how often this crops up. Almost unique, but not very unique. Like someone’s being a bit pregnant.

  17. Jack

    Thank you.
    I downloaded the dictionary and the easy backup zip thingies; trusting in the comments that I won’t get something else with them……..for free ……. ^_^

    I am still having problems when I deleted all my Java – I need a Java Runtime Environment (JRE) to email documents in Microsoft from LibreOffice. I do not have Microsoft Office on my machine. Nothing I do helps me get it back to where it was …………………..:-( ………………….. Any information from anyone would be appreciated.

  18. Archives

    Thank you for this informative and helpful article. How-to-Geek is the best!!!

  19. Sandie

    Thank you, those are wonderful. What I have noticed in the last 30 years of dictionaries is how definitions for words have changed. I have an OLD 3.5 disk from Merriam-Webster Ver 3.1 which I carefully add to each computer since 1995. The definitions on that disk are not politically correct and if you have any interest in how our culture and history has been rewritten, look at an old dictionary or thesaurus.

  20. Kevalin

    “A bit pregnant” can be used as an understatement that jokingly makes a point.

    “Very unique” is just bad grammar.

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