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Illo = Illustration

Illo is short for illustration.
That's a really cute illo!
by Lazygirl January 10, 2006
Abbreviation for illustration, used mainly by the same people who use an abundance of other abbreviations such as LOL, u, r and so forth (otherwise called netspeak and chatspeak) in their online language for no apparent reason.
OMG! Great illo, kewl!
by MrPumpernickel October 08, 2006