As kanji (a Chinese character used in Japanese writing) for "fundoshi" consists of a radical "衣" ("koromo" meaning "vesture") on the left-hand side and "軍" ("gun" meaning "military") on the right-hand side, a fundoshi loincloth traces back to battle dresses.
「褌」の漢字は「衣」偏に「軍」と書くように、戦闘服に由来する。