[adj] concerned with phenomena (especially language) at a particular period without considering historical antecedents; "synchronic linguistics"; "descriptive linguistics"
[adj] occurring or existing at the same time or having the same period or phase; "recovery was synchronous with therapy"- Jour.A.M.A.; "a synchronous set of clocks"; "the synchronous action of a bird's wings in flight"; "synchronous oscillations"
[adj] (of taxa) occurring in the same period of geological time