formicarium UK /ˌfɔː.mɪˈkɛəɹi.əm/US /ˌfɔɹ.mɪˈkɛɹi.əm/ noun1 •A vivarium used for the study of ants and ant colonies.It is on the outskirts of the forest, or around clearings, or near wide roads that let in the sun, that these formicariums are generally found. — 1874 formsformicaria · formicariums