Definition of monophone in English:

monophone

Pronunciation /ˈmɒnəfəʊn/

noun

Phonetics
  • Originally, H. E. Palmer's name for: a phone or phoneme consisting of a single unit of sound. In later use more generally: a phone, as distinguished from speech units comprising more than one phone.

Origin

Late 19th century (in an earlier sense). From mono- + -phone.