Illo is the fannish abbreviation for illustration. Typically, the term is used to describe art in fanzines, but it may also refer to interior art in prozines. Small illos used to fill up white space are called fillos.
An original illo is the original drawing vs. its published iteration. If the illo is hand-stenciled, however, there will be no original. Likewise, computer-created artwork may have no original.
Good fanzine design calls for placing illos so they don't interrupt the text.
|From Fancyclopedia 2, ca. 1959
|An illustration. Either the original or a reproduction may be meant.