Threshold (1990 novel) definition

(1) The sill of a door; a horizontal piece of wood or stone that forms the bottom of a doorway and offers support when passing through a doorway

(2) The entrance (the space in a wall) through which you enter or leave a room or building; the space that a door can close

"He stuck his head in the doorway"

(3) The smallest detectable sensation

(4) A region marking a boundary

(5) The starting point for a new state or experience

"On the threshold of manhood"