Hank m
English: originally a medieval back-formation from Hankin, which is composed of Han (a short form of Jehan JOHN (SEE John)) + the Middle English diminutive suffix -kin. However, the suffix was mistaken for the Anglo-Norman diminutive -in, hence the form Hank, Hank is now sometimes used as an independent given name in America, where it is usually taken as a pet form of HENRY (SEE Henry). It has more or less died out in Britain.
First names dictionary. 2012.