Sir is an honorific address used as a courtesy title to address a man without using his given name or family name in many English speaking cultures. It is often used in formal correspondence (Dear Sir, Right Reverend Sir).The term is often reserved for use only towards one of superior rank or status, such as an educator, or as a form of address from a merchant to a customer. It can also be used by a boy or young man to address an older man.Equivalent terms of address are "ma'am" or "madam" in most cases, or in the case of a very young woman, girl, or unmarried woman who prefers to be addressed as such, "miss". Also, in Australia, Britain and Ireland, female high school teachers are often addressed as "miss" even if they are married. The equivalent term for a knighted woman is Dame, or "Lady" for the wife of a knight.