Coetaneousness is a term that refers to the state of being contemporaneous or belonging to the same time period. However, there are many synonyms for coetaneousness that can be used to convey the same meaning. These include words such as synchronicity, concurrence, simultaneity, contemporaneity, coincidence, and parallelism. Each of these words has a slightly different connotation but can be used interchangeably in most contexts. Synchronicity emphasizes the idea of events happening at the same time, while concurrence emphasizes the idea of multiple factors coming together simultaneously. Simultaneity and contemporaneity both refer to the concept of events occurring at the same time, while coincidence and parallelism both suggest a sense of alignment or connection between events or phenomena.