noun

1. the language used throughout the Greek world, from Syria to Gaul, during the Hellenistic and Roman periods: its spoken form consisted of colloquial Attic, supplemented by borrowings from other dialects: the New Testament is written in the koine
2. a regional dialect or language that has become the common language of a larger area

Etymology: Gr (hē) koinē (dialektos), (the) common (dialect) < koinos: see coeno-