disjunct

Disjunct is a term used in several disciplines with related but distinct meanings.

In logic and mathematics, a disjunct is one of the components of a disjunction, typically expressed with the logical OR operator. For example, in the proposition P ∨ Q, P and Q are disjuncts. A disjunction is true if at least one disjunct is true; both can be true. The concept is fundamental in propositional logic, Boolean algebra, and related fields, where disjuncts may be combined with truth tables and logical rules.

In linguistics, a disjunct (also called a sentence adverb or disjunctive adverb) is a parenthetical element that expresses the speaker’s attitude, evaluation, or stance toward the entire proposition, rather than describing a feature of the proposition itself. Common examples include “frankly,” “fortunately,” “surprisingly,” and “honestly.” Disjuncts are typically syntactically independent of the main clause and may be set off by punctuation; they are distinct from conjuncts and from discourse markers.

In music theory, disjunct motion refers to melodic movement by leaps between pitches, as opposed to conjunct motion, which moves by stepwise intervals. A melody dominated by large intervals is described as disjunct, and the term helps distinguish melodic contour and stylistic characteristics in analysis.

Etymology traces disjunct to the Latin disjunctus, meaning separated or disjoined, from dis- “apart” and iungere “to join.”