More than a dictionary. It’s a comprehensive reference site with synonyms, sentence examples, quotes, biographies, and an amazing collection of grammar-related articles and education resources for students, teachers, parents and homeschoolers.

The world’s biggest online English dictionary, by number of words. Wordnik shows definitions from multiple sources, so you can see as many different takes on a word’s meaning as possible.

Blog tracking new words and phrases in popular use. The Word Lover’s Guide to New Words. Word Spy features new terms that have some traction in the language, meaning that they’ve appeared at least three times in print or online, ideally in significant sources such as newspapers, magazines, and books.

An online tech dictionary for IT professionals, educators and students. We provide definitions to words, phrases and abbreviations related to computing and information technology. Our goal is to provide easy-to-understand definitions, avoiding the use of heavy jargon when possible so that the site is accessible to users with a wide range of computer knowledge.

Combines the world’s smartest dictionary with an adaptive learning capability. Ditch the flash cards and stop memorizing definitions. It teaches you words by systematically exposing you to a wide array of question types and activities that will help you understand all the meanings of every word you’re learning.

Displays a unique visualization of connections between words. Uses ThinkMap technology to visually illustrate linkage between words and ideas.

Dictionary of contemporary American slang. Not appropriate for children.

General and subject dictionaries for financial, legal, and medical terms. Includes a Dictionary, Thesaurus, Dictionaries covering, Legal, Financial Acronyms and Idioms, Encyclopaedia, Wikipedia, The Free Library, More Languages include: Spanish, German, French, Italian, Arabic, Chinese, Polish, Portuguese, Dutch, Norwegian, Greek, Russian, Turkish, Hebrew.

Over 17,000 entries. Find synonyms, antonyms, and brief definitions.

At Oxford Dictionaries, we have just one thing in mind: improving communication through an understanding and passion for language. That explains why we’ve been making dictionaries for more than 150 years and why we continue to innovate and develop new tools and services to suit your language needs as technology and the world around us change.

Meta search tool indexing 13 million words from 1,000 dictionaries. Includes a reverse dictionary that lets you describe a concept and get back a list of words and phrases related to that concept. Your description can be a few words, a sentence, a question, or even just a single word. In most cases you’ll get back a list of related terms with the best matches shown first.

Definitions for thousands of terms in the field of technology and communication including: Internet acronyms, text message jargon, abbreviations, initialisms, cyberslang, leetspeak, SMS code, textese. NetLingo is also tracking a global list of world wide text terms and international online jargon!

Free searchable dictionary and thesaurus, word games, a word of the day, and many other English language and vocabulary reference tools and resources. Based on the print version of Merriam-Webster’s Collegiate Dictionary.

Search over 200,000 medical terms. Covers: Immune System, Musculoskeletal, Nervous System, Paediatrics, Pharmacology, Pregnancy / Gynaecology, Psychiatry / Psychology, Respiratory, Rheumatology, Urology, Cancer / Oncology, Cardiovascular, Dentistry, Dermatology, Emergency Medicine, Endocrinology, ENT, Eyes / Ophthalmology, Gastrointestinal, Haematology.________________________________________

Easy-to-understand explanations of more than 16,000 medical terms. Our doctors define difficult medical language in easy-to-understand explanations of over 16,000 medical terms. Provides quick access to hard-to-spell and often misspelled medical definitions through an extensive alphabetical listing.

Source of mathematical definitions and concept explanations. The World’s most extensive mathematics resource. Covers Algebra, Applied Mathematics, Calculus and Analysis, Discrete Mathematics, Foundations of Mathematics, Geometry, History and Terminology, Number, Theory, Probability and Statistics, Recreational Mathematics, Topology

Whether you’re looking for an obscure phrase or your basic marketing definition, the MarketingPower Dictionary has it all! Originating from the print version in 1995, we’re always adding new terms to keep marketers up to date in the ever-evolving marketing profession.

Features a thesaurus function enabling users to find synonyms for any word, phrase or meaning. There is also a blog with daily postings on language issues, especially on global English and language change. An “Open Dictionary allows users to provide their own dictionary entries for new words they have come across. The online edition has been recognised as a good example of this emerging genre of reference publishing.

Financial glossary with a comprehensive index of 7,500 definitions InvestorWords is the premier online financial glossary and contains over 15,000 definitions, helping millions of individuals understand important concepts required to succeed in today’s financial world. The glossary is updated on a regular basis and covers important topics such as stocks, bonds, banking, accounting, insurance, and forex.

Includes definitions from American Heritage, Random House, and Merriam-Webster. Covers medical terms, abbreviations, cultural matters, science and more.