A room, space, corner or area of a dwelling that is specifically reserved for a male person to be in a solitary condition, away from the rest of the household in order to work, play, involve himself in certain hobbies, activities without interuption. This area is usually decorated by the male that uses it without interferance from any female influence.
Tom retreated to the Man Cave to play his online rpggame.
A term used to describe that one little room (or garage) that the man of the household is given permission by his wife or girlfriend to furnish how he wants and do whatever he wants in it. It should be noted that the word 'man' is used very loosely when referring to a man cave. A real man doesn't allow himself to be shoved into one corner of his own house.
"Sorry, guys. We're going to have to watch the game in my man cave because my wife doesn't want anyone on our living room carpet."
Larry was sent to his man cave by his wife because she was having friends over.