reservoir

res·er·voir

noun \ˈrez-ə(r)v-ˌwär, -ə(r)v-ˌ(w)ȯr\

Definition of RESERVOIR

1

: a space (as an enlargement of a vessel or the cavity of a glandular acinus) in which a body fluid is stored

2

: an organism in which a parasite that is pathogenic for some other species lives and multiplies without damaging its host; also : a noneconomic organism within which a pathogen of economic or medical importance flourishes without regard to its pathogenicity for the reservoir <rats are reservoirs of plague>—compare carrier 1a