Lac, or Gum-Lac, is a substance out of which a species of insects form cells upon trees, like honeycombs. In these cells remain some of the dead insects, which give a red colour to the whole substance of the lac. That called stick-lac is the wax which adheres to some of the small branches of the tree, and is unprepared. This lac, when separated from the adhering sticks, and grossly powdered, and deprived of its colour by digestion with menstruums for the sake of the dyes and other purposes, is called seed-lac, which, when freed from impurities by melting it over a gentle fire, and formed into cakes, is called lump-lac; and, lastly, that called shell-lac consists of the cells liquefied, strained, and formed into thin transparent laminae.

Artificial Lacca, or Lacque, is also a name given to a coloured substance obtained from several flowers, as the yellow from the flower of the juniper, the red from the poppy, and the blue from the iris or violet. The tinctures of these flowers are extracted by digesting them several times in aqua-vitae, or by boiling them over a stove fire in a lixivium of potashes and alum.