Drusilla

wiktionary

ref

Latin Drusilla, feminine diminutive form of the gens name Drusus.

etymonline

ref

Drusilla

fem. proper name, Latin fem. diminutive of Drusus, a frequent surname in Livian gens, earlier Drausus, of uncertain etymology, perhaps a Celtic word meaning literally "strong" (compare Old Celtic *dru- "oak," also "strong;" see Druid).