Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.
AVANT
As described in historical dictionaries
Patronymica Britannica (1860)
AVANT. Probably from Havant, a town in Hampshire; or it may be from the old war-cry, Avant ! " Forward ! "
Origin: English
Region of origin: British Isles
Country of origin: England
Religion of origin: Christian
Language of origin: English