English dictionaries

a nurse is reading a book to a patient in the early 19th century. She is saying "Boring? Come on! I'm only at B."

Online Dictionaries “the big six”

(“The big six” is not an official term. It is not even an unofficial term for insiders. It’s just what I am calling them.)

Cambridge – The online Cambridge Dictionary belongs to Cambridge University Press, which also publishes the Cambridge English courses for non-native speakers that are known as a standard of excellence at many schools all over the world. If English is your second language, this dictionary is a safe bet.

Collins – Collins is based in Scotland and has been around for 200 years. It gives American and British English definitions.

Dictionary.com – Dictionary.com is not backed by a traditional publisher, but is the result of a clever person in 1995 thinking that buying the domain “Dictionary.com” was probably a good idea. It is built on top of the American Webster’s Unabridged Dictionary, but now has its own staff of lexicographers.

Merriam-Webster – calls itself “America’s most trusted dictionary”, has been around for more than 180 years.

Oxford English Dictionary (OED) – this is the dictionary you need when you want to know everything about a word. Every definition a word has ever had since English started being written down is in here. Unfortunately, the OED costs money. If you are a student, you will probably have access through your university. Otherwise, it’s 100 British pounds a year.

Wiktionary – Wiktionary is the only dictionary that is non-profit and is updated by volunteers. Just like Wikipedia, it is part of the Wikimedia foundation. I often find the entries quite helpful, especially where etymology and links to other languages are concerned. But I think that for many English professors, it is not (yet) a “trusted source”.

Online dictionaries that aren’t really their own dictionary

Google search results – google licenses its definitions from the above dictionaries.

Wordnik (uses American dictionaries as its base)

Online genre-dictionaries

Dictionary.com Slang Dictionary

Dictionary.com – Gender and Sexuality

Dictionary of American Regional English

Dictionaries of the Scots language

Oxford Learners’ Dictionaries

Green’s Online Dictionary of Slang

Historical Dictionary of Science Fiction

Urban Dictionary

Defunct online Dictionaries

American Heritage Dictionary is no longer being updated

MacMillan Dictionaryclosed in July 2023, and was taken offline

Paper dictionaries


Webster still exists but is not online

And many more that I have not got round to adding yet…

This list is a work in progress. If you have a link to add, please let me know in the comments below!