Dictionary of Medieval Names
from European Sources

Douglass f. Old Irish dub 'black' + Old Irish glas 'greenish, blueish'.

In 16th C England, this name was used as a woman's name as commonly as a man's.

England
Early Modern English
1584 Dowgles CAmar-vol1 p. 129
Cite as: S.L. Uckelman. "Douglass". In S.L. Uckelman, ed. The Dictionary of Medieval Names from European Sources, Edition 2017, no. 1. http://dmnes.org/2017/1/name/Douglass.