Online Dictionaries

By Xah Lee. Date: . Last updated: .

This page is a list and recommendation of several online English dictionary websites and browser tools. They let you double click on a word in any web page to see its definitions.

Google Chrome dictionary extension 2015-09-25
Google Chrome dictionary extension

Google Chrome Browser Dictionary Extension

If you are using Google Chrome web browser, you can install a extension that lets you double-click on a word in any webpage and its definition will be shown in a pop-up window.

Firefox Extensions

One of Firefox extension i use is QuickWiki. Shift-right-click to lookup a word thru Wiktionary (via pop-up). Control-right-click to lookup Wikipedia.

Download at

Firefox has other dictionary add-ons. Search here: search for dictionary.

List of Online Dictionaries

Here are some popular dictionary sites and their URL search syntax, using sample word “curlicue”.

  1. (AHD, …)
  2. (AHD)
  3. (AHD, Random House, WordNet, …)
  1. (Google)
  1. (WNWC)
  2. (MWC)
  3. (Longman)
  4. (Oxford)
  5. (Oxford Advanced Learner's Dictionary)
  1. (wiktionary)
  2.*&Query=curlicue (1913 Webster, WordNet, …)
  1. (etymology)

When choosing a online dictionary, you want one that's fast loading, not many ads, not cluttered, has human voice recording (as opposed to machine pronounced) for many imported words (Bach, fete, sui generis, …), but most of all, contains the definition from a dictionary you like.

Review of Dictionaries

Here's a quick summary: i highly recommend American Heritage Dictionary. Its vocabulary size is larger than all the others online. Its definition is professional and rich. It is not dumbed-down “explanatory” style as in learner's dictionaries, nor is it terse and incomprehensible as in the abridged “Merriem-Webster collegiate”, nor is it “web samples” as in Word Net.

The worst is the Merriem-Webster COLLEGIATE dictionary. It is a abridged dictionary and very popular due to i suppose aggressive marketing. Also, extremely bad is the dictionary bundled with every Mac OS X: New Oxford American Dictionary. It is a “learner's dictionary” and a bad one.

What's Learner's Dictionary?

“Learner's dictionary” is a class of dictionaries that take a explanatory approach. Instead of giving a definition, it simply explains what the word means. This is great if you are a casual reader and simply want to know a word's meaning quickly, but it has several serious problems.

  1. You won't be able to understand a word unless it is used in the most common way. Because, learner's dictionary usually omits a word's less popular meanings.
  2. It does not give you any sense at all of the word's connotation, background, etymology. If you are reading a old classic English novel (e.g. Jonathan Swift), or finely-crafted journalism such as Time Magazine articles, learner's dictionary will puzzle and mislead you.

For in-depth review of dictionaries, see:

For Emacs

If you are a emacs user, see: Emacs: Lookup Google, Dictionary, Documentation.