nonsimultaneously

Nonsimultaneously is an adverb meaning not occurring at the same time; not concurrent. It describes actions, events, or processes that do not take place at the exact same moment as another. It is formed from non- (not) + simultaneous (occurring at the same time) + -ly (adverb suffix).

In everyday use, nonsimultaneously can refer to events that are ordered in time but do not overlap. For example, two announcements may be made nonsimultaneously, or a pair of tasks may be completed nonsimultaneously, one finishing before the other begins.

In scientific contexts, nonsimultaneously is used when discussing timing of events. In physics, whether two spatially separated events are simultaneous depends on the observer’s frame of reference, so they may be nonsimultaneous in one frame but not in another. In experimental design and data recording, signals or measurements are sometimes described as nonsimultaneous when timing precision prevents true simultaneity.

Etymology and usage notes: the term emphasizes temporal ordering rather than duration. It is often used in contrast to simultaneously or concurrently. See also: simultaneity, sequential, asynchronous.