Main Entry: sir

Pronunciation: \ˈsər\

Function: noun

Etymology: Middle English, from sire

Date: 13th century

1 a : a man entitled to be addressed as sir —used as a title before the given name of a knight or baronet and formerly sometimes before the given name of a priest b : a man of rank or position
2 a —used as a usually respectful form of address b capitalized —used as a conventional form of address in the salutation of a letter