I just tried make a one liner to get info about keywords from Wikipedia.

This is just an idea can be further advanced , the command is just use of the wiki dns and few utilities like dig and zenity.

<b>
zenity --info --text="$(dig +short txt $(zenity --entry --title="Search wiki" --text="Enter your search word:").wp.dg.cx)"
</b>

Sample output :
Say if the search term was "Ubuntu" , the output would be :

"Ubuntu ( in English, in Zulu) is a computer operating system based on Debian GNU/Linux. Its name comes from the Zulu word "ubuntu", translated as "humanity to others", describing the ubuntu philosophy: "I am what I am because of who we all are", a positiv" "e aspect of community. Ubuntu's goals include providing an up-to-date, stable operating system for the average user, with a... http://a.vu/w:Ubuntu"

Download the file and place it in /bin and make a custom application launcher or just use it as a plain cli app.