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1. Occurring or existing at the same time or having the same period or phase
   - synchronous, synchronal
    
2. Concerned with phenomena (especially language) at a particular period without considering historical antecedents
   "synchronic linguistics"
    
3. (of taxa) occurring in the same period of geological time

See also: coetaneous, coeval, coexistent, coexisting, coincident, coincidental, coinciding, concurrent, contemporaneous, contemporary, co-occurrent, cooccurring, parallel, simultaneous, synchronised [Brit], synchronized, synchrony

Antonym: diachronic

Encyclopedia: Synchronic