complementary (adj.)

A term used primarily in PHONOLOGY in the phrase complementary distribution, referring to the mutual exclusiveness of a pair of sounds in a certain PHONETIC ENVIRONMENT. In English, for example, the voiceless ALLophone of the /l/ phoneme occurs after initial /p-/, as in plan, and the VOICED allophone is excluded; conversely, [l] is used initially when no /p-/ precedes. [$] and [l] are thus said to be ‘in complementary DISTRIBUTION’ in this environment. The term is also used analogously in MORPHOLOGY, with reference to the distribution of pairs of FORMS in GRAMMATICAL environments (e.g. the selection of alternative forms of plural MORPHEME in English).

In SEMANTICS, the term is often used to refer to a category of SENSE relation between LEXICAL ITEMS. Complementary terms (or complementaries) display a type of oppositeness of MEANING, illustrated by such pairs as single/ married and boy/girl. Single is said to be ‘the complementary of’ married, and vice versa. In such a relationship, the assertion of one of the items implies the denial of the other: an entity cannot be both at once. The relationship of complementarity is characterized by the lack of any gradability between the items (there is no continuum of gradation between boy and girl, such that one can be *less boy, *very boy, and so on). In this respect, the term contrasts with the technical sense of ANTONYMY, where gradations between the opposites are possible (cf. big, bigger, very big, etc. v. small, smaller, etc.), and also with CONVERSENESS, where the opposites presuppose each other (e.g. husband/wife). The term CONTRADICTORY is an alternative preferred by some analysts.