a low shrubby tree of the genus pistacia (p. lentiscus), growing upon the islands and coasts of the mediterranean, and producing a valuable resin; -- called also, mastic tree.-a resin exuding from the mastic tree, and obtained by incision. the best is in yellowish white, semitransparent tears, of a faint smell, and is used as an astringent and an aromatic, also as an ingredient in varnishes.-a kind of cement composed of burnt clay, litharge, and linseed oil, used for plastering walls, etc.