The Online Etymology Dictionary is available for free on the Internet. You can enter a word, or part of a word, a suffix for instance, that you are interested in in the form on the frontpage or start your search with a click on one of the letters of the alphabet.

If you’d enter Etymology for instance you get the following information:

late 14c., ethimolegia “facts of the origin and development of a word,” from O.Fr. et(h)imologie (14c., Mod.Fr. étymologie), from L. etymologia, from Gk. etymologia, properly “study of the true sense (of a word),” from etymon “true sense” (neut. of etymos “true, real, actual,” related to eteos “true”) + -logia “study of, a speaking of” (see -logy). In classical times, of meanings; later, of histories. Latinized by Cicero as veriloquium. As a branch of linguistic science, from 1640s. Related: Etymological; etymologically.

Information usually consists of one or multiple sentences. The related information are unfortunately not displayed as links, which means that you have to manually copy and paste them to perform a search on them.

One of the things that I like to do is to look up suffixes and prefixes, as they can help you get an understanding of a word even if you do know know what it means exactly. The suffix -itis for instance denotes diseases characterized by inflammation.

The etymology dictionary makes a handy bookmark for users who like to look-up word meanings and a word’s history. Just head over to the site and start searching, and maybe share a word you discovered with the rest of us.

Here is how the Firefox add-on works. Wikilook offers several methods of looking up words on web pages. The unobtrusive approach works by pressing the shift key and moving the mouse over a word that needs to be looked up in a dictionary.

This will automatically open a small popup window next to the word or phrase that should be looked up in the dictionary. The word definition will stay on the screen until the left mouse button is pressed by the user which closes the popup window.

Word phrases can also be looked up in dictionaries. This is done by selecting the phrase with the left-mouse button before pressing shift and holding the mouse cursor over the phrase. This will then look up the selected phrase in the dictionary. It is possible to follow links that are displayed in the dictionary popup window. A left-click would open the page in the same tab. A middle-click or pressing Ctrl while left-clicking will open the link in a new tab instead.

WikiLook can also look up words in Wikipedia and Uncyclopedia. These look ups are initiated by pressing the Ctrl or Alt keys and right-clicking on a word or phrase that should be looked up. These functionality did not work properly on our Windows XP test system with Firefox 3.5.2 installed. It could be that another Firefox add-on interfered with this option though. If any of you who install the add-on can get this to work let us know.

The English pages of Wikipedia, Wiktionary and Uncyclopedia are used by default. Users who want to access dictionary definitions in other languages can change the English pages in the options easily to other language pages. The add-on comes with advanced settings that can only be accessed in the about:config menu. Easiest way to do so is to filter for wikilook in the configuration menu.

Most of the configuration settings define aspects of the popup window that is displaying the dictionary definitions.

Wikilook provides one of the most unobtrusive ways of looking up words in dictionaries saving users who do so regularly lots of time.