a suffix occurring in loanwords from Latin, which often denote a location or receptacle (armarium; caldarium; solarium; vivarium). It has limited productivity in English, esp. in words denoting an artificial environment for plants or animals, on the model of vivarium or herbarium: aquarium; insectarium; terrarium. Cf. -ary.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.