The plank, stone, or piece of timber, which lies under a door, especially of a dwelling house, church, temple, or the like; the doorsill; hence, entrance; gate; door.
- A piece of wood or stone placed beneath a door; a doorsill.
- An entrance or a doorway.
- The place or point of beginning; the outset.
- The point that must be exceeded to begin producing a given effect or result or to elicit a response: a low threshold of pain.