Main Entry: ob·li·gate

Pronunciation: \ˈäb-li-gət, -lə-ˌgāt\

Function: adjective

1 : restricted to one particularly characteristic mode of life or way of functioning <the infant is an obligate nose breather—Journal of the American Medical Association> <an obligate parasite>
2 : biologically essential for survival <obligate parasitism>

—ob·li·gate·ly adverb