From Latin 'honor' (esteem, public office) — a cornerstone of Norman chivalric vocabulary that shaped how English frames reputation.
High respect or great esteem; adherence to what is right or to a conventional code of conduct.
From Anglo-Norman 'honur,' from Old French 'onor' or 'honor' (modern French 'honneur'), from Latin 'honōrem' (accusative of 'honor' or 'honos'), meaning 'honor, dignity, office, reputation.' The Latin word is of uncertain further etymology, possibly Italic or pre-Latin substrate. 'Honor' entered English as part of the Norman aristocratic vocabulary
The spelling split between American 'honor' and British 'honour' preserves a medieval disagreement. The Latin original was 'honor,' the Old French form was 'onor' or 'honour' (with French spelling conventions), and English inherited both traditions. Noah Webster chose the Latin-style spelling for his 1828 American dictionary, while British English kept the French