TRICHOTOMY

trichotomy

(noun) being threefold; a classification into three parts or subclasses

Source: WordNet® 3.1

Etymology

Noun

trichotomy (countable and uncountable, plural trichotomies)

Division or separation into three groups or pieces.

(algebra) the property of an order relation whereby, given an ordered pair of elements (of a given algebraic structure), exactly one of these is true: the first element is 'less than' the second one, the second is 'less than' the first, or the two elements are equal.

Source: Wiktionary

Tri*chot"o*my, n. Etym: [Gr. tri`cha threefold, in three parts + te`mnein to cut or divide: cf. F. trichotomie.]

Definition: Division into three parts.

Source: Webster’s Unabridged Dictionary 1913 Edition