DOUBLET, noun 1. The inner garment of a man; a waistcoat or vest. 2. Two; a pair. 3. Among lapidaries, a counterfeit stone composed of two pieces of crystal, with a color between them, so that they have the same appearance as if the whole substance of the crystal were colored.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI