Bill Cosby -- Raven Symone Blasts Rape Rumor ... That's Disgusting!

At least one Bill Cosby rape claim is being shot down by the alleged victim -- his former 'Cosby Show co-star Raven Symoné says he NEVER touched her ... despite a story that's gone viral.

A parody website posted a story earlier this week claiming Raven was telling people Cosby had sexually assaulted her ... which is especially sick, considering she was only 3 years old when she debuted as Huxtable granddaughter, Olivia.

Raven finally responded Wednesday afternoon ... saying she was NOT taken advantage of by Cosby ... and ... "This is a truly disgusting rumor that I want no part of!"

In the Instagram post she added ... "Keep me out of this."