Recurs

Recurs is the third-person singular present tense form of the English verb recur, meaning to happen again or repeatedly, or to return after an interval. In usage, recurs describes patterns or events that reappear despite time or intervention. The word comes from the Latin recurrere, from re- meaning back and currere to run.

Recurs is commonly found in scientific, medical, and everyday writing. Examples: “The cough recurs every winter,” “If costs recurs annually, budgeting should adjust,” or “The issue recurs despite the fixes.” It is distinct from recurrence, which is the noun describing the act or instance of recurring, and from recursion, a related concept in mathematics and computer science that involves self-reference.

Morphology: the verb recur has the present tense form recurs for third-person singular; past tense recurred; present participle recurring; past participle recurred. Some style guides prefer consistent spelling of past forms as recurred, though recurred is less common in contemporary usage than recurred for the past tense.

Usage notes: avoid overuse in formal prose; consider synonyms such as reappear, reoccur, or repeat depending on nuance. In technical contexts, recurs often appears when noting repeating phenomena, while recurrence or recurrence relations may be used when the focus is on the pattern itself or its mathematical description.

See also: recurrence, recurring, recurrence relation, recursion.