n. A little face; a small surface; specifically, in lapidary work, a small polished surface, usually of some geometrical form; one of the many variously shaped segments or faces into which the surface of a gem is broken in order to increase its brilliancy.n. In architecture the fillet between the flutings of a column.n. In anatomy, a smooth, flat, circumscribed articular surface of bone. See second cut under dorsal.n. In entomology, the surface of an ocellus of the compound eye of an insect; also, an ocellus.To cut a facet or facets upon: as, to facet a diamond.n. A book; especially, a child's book of instruction; a primer.n. In the embryo of Pentastomum, the circular thickening left on the detached integument at the site of the dorsal cone after the separation of the embryo from the integument. Also facette. Compare cervical cross.