Slang for an autistic person. Nobody knows precisely when this term came into use, but it's a diminuitive form of the word autistic. Rumors say it was originally in common use by professionals, and eventually came to be equivalent in callousness to the derogatory term retard.
These days, a lot of autistic people use the term to describe themselves, or even as a term of "autie pride". Especially popular among autistic people who don't have Asperger's syndrome, even though it can refer to anyone on the autistic spectrum. Sometimes, but not always, offensive when used by neurotypicals.
See also aspie.
Example usage: "Do you know of any auties who live in the Los Angeles area?"