n. (Chem.) A retinoid compound (C20H28O2), closely related to vitamin A. It is also called tretinoin and vitamin A acid. [ PJC ]

a. [ Gr. &unr_;&unr_;&unr_; resin + -oid. ] Resinlike, or resinform; resembling a resin without being such. [ 1913 Webster ]

n. [ Gr. &unr_;&unr_;&unr_; resin + L. oleum oil. ] 1. (Chem.) A hydrocarbon oil C32H16, obtained by the distillation of resin, -- used as a solvent, as an antiseptic, and in printer's ink. [ 1913 Webster +PJC ]

2. One of the compounds which function as vitamin A. Called also vitamin A, vitamin A1 and vitamin A alcohol. See vitamin A1. [ PJC ]