Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.
GILLET
As described in historical dictionaries
Patronymica Britannica (1860)
GILLET. (in jjronunciation Jillet.) The name is supposed to be derived from Gilleste, a town on the borders of France and Piedmont. Inf. Rev. Edw. Gillet. When tlie G is hard, the name is probably a derivation of Guillaume, William.
Origin: English
Region of origin: British Isles
Country of origin: England
Religion of origin: Christian
Language of origin: English