Sir

A polite title used to address a man, especially someone you don’t know well or who has authority. In Britain, it is also used as a title for a man who has been given a special honor by the king or queen.

“Sir” comes from Middle English “sire,” which meant “lord” or “father.” That word traces back to Old French and Latin “senior,” meaning “older” or “elder.” Over time, it shifted from meaning a powerful lord to a general respectful title.