monophone
/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. Compare ancient Greek μονόϕωνος with one voice or tone, French monophone.