threshold

英['θreʃəʊld;'θreʃ,həʊld] 美['θrɛʃhold]

1. the starting point for a new state or experience;

"on the threshold of manhood"

2. the smallest detectable sensation

3. 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"

4. the sill of a door; a horizontal piece of wood or stone that forms the bottom of a doorway and offer support when passing through a doorway

5. a region marking a boundary