Main Entry: Mr.

Pronunciation: \ˈmis-tər, in rapid speech especially in sense 2 (ˌ)mis(t)\

Function: noun

Inflected Form(s): plural Messrs.\ˈme-sərz\

Etymology: Mr. from Middle English, abbreviation of maister master; Messrs. abbreviation of Messieurs, from French, plural of Monsieur

Date: 15th century

1 —used as a conventional title of courtesy except when usage requires the substitution of a title of rank or an honorific or professional title before a man's surname <spoke to Mr. Doe>
2 —used in direct address as a conventional title of respect before a man's title of office <may I ask one more question, Mr. President>
3 —used before the name of a place, profession, or activity or before an epithet (as clever) to form a title applied to a male viewed as representative of the thing indicated <Mr. Baseball>