Example:
Man to woman at door: "Please, <em>after you</em>, go ahead." 
Photo license:
CC: Attribution, Commercial Use
Regionalism:
Neutral
Regional variant:
Neutral
Full Expression:
Etiquette: after you
Used to invite a person to pass in front of you, often when walking through a door This shows respect. A man or a woman can use this expression, though it is more commonly used by men.