Blain is a Scottish surname derived from the Irish given name Bláán. This personal name originates from Old Irish blá meaning "yellow" combined with a diminutive suffix, giving it the sense of "little yellow one" or "yellow-haired." Bláán was borne by a 6th-century Irish saint who served as a bishop of Kingarth on the Isle of Bute, Scotland, contributing to the name's adoption in Scottish naming traditions. Saint Bláán is also known as Saint Blane. As a surname, Blain is an anglicized variant that emerged after the Norman influence and subsequent phonetic modifications. The related form Blaine, a variant of Blain, has also been used both as a surname and a given name. The surname Blain, however, has been more established in Scotland and parts of Northern Ireland.