Mas"tic (?), n. [F., fr. L. mastiche, mastichum, Gr. &?;, fr. &?; to chew, because of its being used in the East for chewing.] [Written also mastich.]

1. (Bot.) 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.

2. 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.

3. A kind of cement composed of burnt clay, litharge, and linseed oil, used for plastering walls, etc.

Barbary mastic(Bot.), the Pistachia Atlantica. -- Peruvian mastic tree(Bot.), a small tree (Schinus Molle) with peppery red berries; -- called also pepper tree. -- West Indian mastic(Bot.), a lofty tree (Bursera gummifera) full of gum resin in every part.