From Old French feudal vocabulary, encoding a relationship of lord and vassal into a single word.
Loyalty or commitment to a superior, group, cause, or country.
The word allegiance entered English in the late 14th century from Anglo-French allegeance, itself formed from Old French ligeance (the duty owed by a vassal to a liege lord). The Old French term derived from lige (liege, bound), which traces to Medieval Latin ligius, possibly from a Frankish or other Germanic source meaning "free" — a paradox, since the liege was both free-born and bound by oath. The prefix al- is a variant of ad- (to), giving the sense of "binding