Definition of idiomatism in English:

idiomatism

Pronunciation /ˌɪdɪˈəʊmətɪz(ə)m/

noun

rare
  • An idiomatic expression.

Origin

Late 18th century; earliest use found in The Annual Register. From classical Latin idiōmat-, idiōma or its etymon Hellenistic Greek ἰδιώματ-, ἰδίωμα idiom + -ism.