Coterminously is an adverb used to describe two or more events or conditions happening at the same time, or having the same boundary. There are several synonyms for coterminously such as simultaneously, concomitantly, contemporaneously, coextensively, and concordantly. Simultaneously and concomitantly emphasize the concurrent occurrence of events, while contemporaneously highlights the temporal relationship between events. Coextensively refers to two things that have the same extent or boundaries, while concordantly describes things happening in agreement. These synonyms can be used interchangeably with coterminously to describe the concurrent nature of events, relationships or conditions.