reservatory

from The Collaborative International Dictionary of English v.0.48

Reservatory \Re*serv"a*to*ry\ (-t?-r?), n. [LL.
   reservatorium,fr. L. resservare. See {Reserve}, v. t., and
   cf. {Reservior}.]
   A place in which things are reserved or kept. --Woodward.
   [1913 Webster]