む, in hiragana, or ム in katakana, is one of the Japanese kana, which each represent one mora.

In older Japanese texts until the spelling reforms of 1900, む was also used to transcribe the nasalised [ɴ].

Since the reforms, it is replaced in such positions with ん.

In the Ainu language, ム can be written as small ㇺ, which represents a final m sound.

[1] This, along with other extended katakana, was developed by Japanese linguists to represent Ainu sounds that do not exist in standard Japanese katakana.