On (Japanese prosody)

The term "On" (rarely "Onji") refers to counting phonetic sounds in Japanese poetry. In the Japanese language, the word "on" (音) means "sound". It is used to mean the phonetic units counted in haiku, tanka, and other such poetic forms. Known as "morae" to English-speaking linguists, the modern Japanese term for the linguistic concept is either haku () or mōra ().