The Collaborative International Dictionary of English v.0.48:
Lac \Lac\, n. [Per. lak; akin to Skr. l[=a]ksh[=a]: cf. F.
lague, It. & NL. lacca. Cf. Lake a color, Lacquer,
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.