Biology. restricted to a particular condition of life, as certain organisms that can survive only in the absence of oxygen: obligate anaerobe (opposed to facultative).
Origin of obligate
1400–50;late Middle Englishobligat (adj.) < Latinobligātus (past participle of obligāre to bind), equivalent to ob-ob- + ligātus; see ligate
Related formsob·li·ga·ble[ob-li-guh-buh l]/ˈɒb lɪ gə bəl/, adjectiveob·li·ga·tor, nounnon·ob·li·gat·ed, adjectivepre·ob·li·gate, verb (used with object),pre·ob·li·gat·ed,pre·ob·li·gat·ing.qua·si-ob·li·gat·ed, adjectivere·ob·li·gate, verb (used with object),re·ob·li·gat·ed,re·ob·li·gat·ing.un·ob·li·gat·ed, adjectiveCan be confusedobligateoblige
to compel, constrain, or oblige morally or legally
(in the US) to bind (property, funds, etc) as security
adjective
compelled, bound, or restricted
biologyable to exist under only one set of environmental conditionsan obligate parasite cannot live independently of its host Compare facultative (def. 4)
1540s, "to bind, connect;" 1660s, "to put under moral obligation," back-formation from obligation, or else from Latin obligatus, past participle of obligare (see oblige). Oblige, with which it has been confused since late 17c., means "to do one a favor." Related: Obligated; obligating.
Capable of existing only in a particular environment or by assuming a particular role. An obligate aerobe, such as certain bacteria, can live only in the presence of oxygen. An obligate parasite cannot survive independently of its host. Compare facultative.
