M (letter)

The letter M is the 13th character of the Latin alphabet. This article explains its sound, shapes, historical origin, common uses (including Roman numeral and SI symbol) and typographic notes.

M is the thirteenth letter of the English and Latin alphabets. It typically represents the voiced bilabial nasal consonant sound, as in words such as "mother" or "map." The letter appears in uppercase (M) and lowercase (m) forms and is a fundamental character for writing, printing and digital text.

Form and sound

Phonetically, the usual value of M is the voiced bilabial nasal: the lips close while air is released through the nose. In standard orthographies that use the Latin script, M is a consonant letter with similar function across many languages. Visually, the uppercase M is composed of four strokes forming a peaked shape, while the lowercase m commonly has three arches or a single rounded form in some typefaces.

History and development

The letter traces back through the Greek letter Mu and before that to the Phoenician letter mem. Its ultimate origin is widely traced to a Semitic root whose name and pictogram were associated with water. For readers interested in the deeper lineage, see the article on Semitic mem. The letter entered Latin and then the modern English alphabet; for context on its place in English, see English alphabet and on its classical role in the Latin alphabet.

Uses and examples

As a letter: appears in countless words and names across languages that use Latin script.
As a symbol: lowercase m is the standard symbol for the SI unit metre in scientific contexts.
As a numeral: uppercase M has been used historically as a Roman numeral for one thousand.

M is also used informally as an abbreviation in various contexts and appears in codes, labels and notation systems. Its frequency in texts is moderate compared with other consonants, and typographers pay attention to its weight and symmetry to preserve legibility.

Notable distinctions include variations in handwritten and printed forms, differences in pronunciation across languages (some languages use it in consonant clusters, others reduce or assimilate it), and its symbolic roles in science and numbering. The simple shape and clear sound have made M a stable and widely recognized element of modern alphabets.