National Institute of the Korean Language (Naver.com mirror)(accessed 2006-12-31),“머리”, in표준국어대사전
Seo Jeong-beom (서정범)(2000),“머리”, in國語語原辭典, Seoul: Bogosa Books, page 246
Etymology
Of native Korean origin.. Found in early records as 마리 (mari). Believed to arise from the root 맏 (mat), which is fossilized in constructions such as 맏아들 (madadeul) ("eldest son").