The word 'squire' entered English in the 13th century from the Old French 'esquier', which itself derived from the Late Latin 'scutarius', meaning 'shield-bearer'. This Latin term was formed from 'scutum', the word for a large, oblong shield used by Roman infantry. The role of a shield-bearer was a crucial one for a knight, and the term 'esquier' in Old French came to denote a young man of noble birth who served as an attendant to a knight, carrying his shield and armor. Over centuries, as the feudal system evolved, the meaning broadened in English. The military attendant role faded, and the title became associated with a country gentleman and landowner, reflecting a shift from a martial duty to a social and territorial standing, while retaining the core idea of a person of status.

The word is a simplex loanword from Old French. Its spelling and form have been fully integrated into English and cannot be meaningfully segmented into productive morphemes using its modern English spelling.