look up any word, like blumpkin:
 
1.
All people whose existence the speaker deigns to acknowledge. Generally limited to those with similar interests and vocabulary.
Everybody knows that Super Metroid is the greatest game ever made. (everybody = video gamers who have played Super Metroid, whose favorite genre is the adventure-platformer)

Everybody lost money in the dotcom bust. (everybody = investors in the dotcom bubble)
by Logical Dash February 09, 2006
 
2.
a person who is versatile in various fields.
He is a composer, a singer, a musician, a painter, a dancer and what not. In fact, he is an everybody.
by uttam maharjan September 19, 2010
 
3.
Something that they sing on homestarrunner.com in the theme song.
Everybody! Everybody! Eveybody! La de do da do.
by Josh August 02, 2003