The Collaborative International Dictionary
Lac \Lac\, n. [Per. lak; akin to Skr. l[=a]ksh[=a]: cf. F. lague, It. & NL. lacca. Cf. Lake a color, Lacquer, Litmus.] A resinous substance produced mainly on the banyan tree, but to some extent on other trees, by the Laccifer lacca (formerly Coccus lacca), a scale-shaped insect, the female of which fixes herself on the bark, and exudes from the margin of her body this resinous substance.
Note: Stick-lac is the substance in its natural state, incrusting small twigs. When broken off, and the coloring matter partly removed, the granular residuum is called seed-lac. When melted, and reduced to a thin crust, it is called shell-lac or shellac. Lac is an important ingredient in sealing wax, dyes, varnishes, and lacquers.
Ceylon lac, a resinous exudation of the tree Croton lacciferum, resembling lac.
Lac dye, a scarlet dye obtained from stick-lac.
Lac lake, the coloring matter of lac dye when precipitated from its solutions by alum.
Mexican lac, an exudation of the tree Croton Draco.
Wiktionary
n. (dated form of shellac English)