D defs.my
Entry 2 senses Webster, 1913

Threshold

/thrĕsh'-ōldˌ/ · Thresh·old · IPA /ˈθɹɛʃ(h)oʊld/
01 n. The plank, stone, or piece of timber, which lies under a door, especially of a dwelling house, church, temple, or the like; the doorsill; h…
  1. 1.
    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.
  2. 2.
    Fig.: The place or point of entering or beginning, entrance; outset; as, the threshold of life.