What is the meaning of Koiné?

Alternative spelling of koine

koine (a lingua franca)

Koine (language)

Koine (common supra-regional form of Greek spoken and written during the Hellenistic period, the Roman Empire, and the early Byzantine Empire)

koine (regional language that becomes standard over time)

Koine (the common Greek language during late antiquity)

koine (form of language resulting from dialect-levelling)

Koine (variety of the Greek language used in the Hellenistic period)

Source: wiktionary.org