Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.
SLATE
As described in historical dictionaries
Patronymica Britannica (1860)
SLATE. An Edinburgh surname. Perhaps from Sleat, a parish of Invernessshire. 2. iSlait or slafr slovenly and dirty. Jamieson.
Origin: English
Region of origin: British Isles
Country of origin: England
Religion of origin: Christian
Language of origin: English