LATCH

[noun] [C] - a device for keeping a door or gate closed without locking it that consists of a movable bar which fits into a hole and which is lifted by pushing down on another bar(UK) Some locks have a button on the inside of a door which can prevent the door from being opened from the outside, and if a door with such a lock is on the latch, the button is in a position which allows the door to be opened.Don't forget to leave the front door on the latch if you go to bed before I get back.