c. 1200, norice, nurrice, "wet-nurse, woman who nourishes or suckles an infant; foster-mother to a young child," from Old French norrice "foster-mother, wet-nurse, nanny" (source of proper name Norris), from Late Latin *nutricia "nurse, governess, tutoress," noun use of fem. of Latin nutricius "that suckles, nourishes," from nutrix (genitive nutricis) "wet-nurse," from nutrire "to suckle" (see nourish).
The modern form of the English word is from late 14c. By 16c. also "female servant who has care of a child or children" (technically a dry-nurse). As "one who protects or that which nurtures, trains, or cherishes," from early 15c. Meaning "person (usually a woman) who takes care of sick or infirm persons" in English is recorded by 1580s.
"an overflowing, a flood," early 15c., from Latin inundationem (nominative inundatio) "an overflowing," noun of action from past-participle stem of inundare "to overflow," from in- "onto" (from PIE root *en "in") + undare "to flow," from unda "a wave," from PIE *unda-, nasalized form of root *wed- (1) "water; wet."