Synonyms for Synchronous (same or very similar meaning)
WordNet sense 1 ((of taxa) occurring in the same period of geological time):
synchronic
WordNet sense 2 (occurring in the same period of time):
contemporaneous, contemporary
WordNet sense 3 (occurring or operating at the same time):
concurrent, simultaneous
WordNet sense 4 (occurring or existing at the same time or having the same period or phase):
synchronal
From the ODE community, based on WordNet
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