1. a compound among the group of taxanes derived from the bark and other organs of the Pacific yew (Taxus brevifolia) and other yews used as a drug for the treatment of advanced ovarian cancer 2. the drug paclitaxel with a complex ring structure (C₄₇H₅₁NO₁₄), used in medicine and having the registered name Taxol®This definition last updated 09/18/2008