M̃

M̃ (majuscule: M̃, minuscule: m̃) is a Latin M with a diacritical tilde.

The characters "M̃" (uppercase) and "m̃" (lowercase) consist of the Latin letter M with a combining tilde diacritic (U+0303), represented in Unicode as U+004D or U+006D followed by U+0303 to ensure broad compatibility across digital platforms. While precomposed forms of M̃ are not included in the primary Latin-1 supplement, these combining sequences enable accurate rendering in HTML (e.g., "M̃") and LaTeX (via \verb|~{M}|). Input methods on major operating systems — such as Windows's US International keyboard, macOS's Option + n dead key, and Linux compose-key sequences — support the combining tilde with minimal configuration.

In linguistics, M̃ appears chiefly in phonetic transcription and the orthographies of a few languages and dialects to denote features such as nasalization, denasalization or secondary articulation. It is used in the International Phonetic Alphabet for denasalized consonants and specialized Americanist notations for unreleased or partially nasal segments . Minority and constructed languages employing M̃ include certain notations of Proto-Indo-European reconstructions, Mapudungun phonemic studies, and some orthographies of Central American indigenous languages; in these contexts, it is typically called "m tilde" and occurs infrequently relative to other diacritic combinations.