M, or m, is the thirteenth letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is em (pronounced /ˈɛm/), plural ems.[1]
The letter M is derived from the Phoenician Mem, via the Greek Mu (Μ, μ). Semitic Mem is most likely derived from a "Proto-Sinaitic" (Bronze Age) adoption of the "water" ideogram in Egyptian writing. The Egyptian sign had the acrophonic value /n/, from the Egyptian word for "water", nt; the adoption as the Semitic letter for /m/ was presumably also on acrophonic grounds, from the Semitic word for "water", *mā(y)-.[2]
The Oxford English Dictionary (first edition) says that ⟨m⟩ is sometimes a vowel, in words like spasm and in the suffix -ism. In modern terminology, this is described as a syllabic consonant (IPA /m̩/).
The letter ⟨m⟩ represents the voiced bilabial nasal /m/ in the orthography of Latin as well as in those of many modern languages.
In Washo, lower-case ⟨m⟩ represents a voiced bilabial nasal /m/, while upper-case ⟨M⟩ represents a voiceless bilabial nasal /m̥/.