smallermediumlarger Definition of STL2STL2: Stickler syndrome, type II. See: Stickler syndrome. Last Editorial Review: 10/9/2012 Search MedTerms:Back to MedTerms online medical dictionary A-Z List Need help identifying pills and medications? Use the pill finder tool on RxList. Share this Article: Facebook Twitter Email Print Article STAY INFORMED Get the latest health and medical information delivered direct to your inbox!