That is solved with the extension at https://addons.mozilla.org/en-US/firefox/addon/240/ which adds all your installed search engines.

More info on changing those engines at http://support.mozilla.com/en-US/kb/Search+bar#Managing_search_engines Note: if you've removed the search bar you can still edit the engines by pasting chrome://browser/content/search/engineManager.xul into the address bar.

That context menu entry uses whichever search engine is selected in the search bar. Select Wikipedia as the search engine in the search bar and the context menu item will be "Search Wikipedia for '_"

Given addon does not work for firefox 4.

Also can some one provide solution in which we don't need to change search engine in search bar.

An addon is not a solution. I don't want to install more crap on my computer. I just want to make the slightest change that would make my life quite a bit easier. I am living in an international dorm in Japan. I frequently need to translate from 3 different languages to English to understand people. Changing google translate's settings is a chore, as is constantly copying text and running to the tab, which is often on another desktop dedicated to translating other materials. The search bar is just as cumbersome, as it requires a lot more mouse movement than necessary. I like keyboard shortcuts, or something I can click and select very quickly and convenient. The current arrangement is neither. This is a computer program. It is made of code, and controlled by files on my computer. What code in what file do I alter in what way to achieve the desired result? The file in question is assumedly userChrome.css, which must be created in the chrome folder in the profile folder by altering userChrome-example.css and saving it under the proper name. Now, how do I alter it to add an empty search string to my context menu?

Google chrome would have made this so easy...but I quit using it because they have a design policy against customization. Help me, Mozilla, you're my only hope.