Onsetwhen

Onsetwhen is a term used in linguistics and natural language processing to denote the moment at which an event or state begins, functioning as a temporal index or operator. The word is a blend of onset, the starting point of an event, and when, a temporal specification. It is not a standard entry in grammars, but appears in theoretical discussions of event semantics and in some computational models that handle time and sequencing.

In formal semantics, onsetwhen can be defined as a function that, given an event predicate P and a discourse context, returns a time t such that the event described by P begins at t. It helps anchor tense, aspect, and temporal modifiers. For example, if P is “the door opens,” onsetwhen(P) = t_open, the moment the door begins to open. In sentences like “When the bells rang, the crowds dispersed,” onsetwhen(ringing) supplies the reference time for the main clause and helps link it to accompanying temporal information.

Applications and status: Onsetwhen is used mainly in theoretical models and experimental annotations rather than as an established grammatical category. It is relevant to event extraction, temporal reasoning in natural language processing, and video understanding, where identifying the onset of actions improves sequencing and narration accuracy.

See also: onset, when (temporal conjunction), event semantics, temporal reasoning.