myEtymology.com: Greek etymology of diphthongos

Etymology of the Greek word diphthongos (δίφθογγος)

the Greek word diphthongos, δίφθογγος

derived from the Greek word di-, δι-, δί-

derived from the Greek word dis, δίς (double; twice)

derived from the Medieval Greek word phthongos, φθόγγος (utterance; a musical note (vocal or instrumental))