noun a kind of cement composed of burnt clay, litharge, and linseed oil, used for plastering walls, ·etc.
2. mastic ·noun 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.
3. mastic ·noun 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.