Doorsill
Part of speech: noun
Definition: The horizontal piece of wood, stone or metal at the threshold of a doorway; a doorstep
Threshold
Part of speech: noun
Definition: The bottom-most part of a doorway that one crosses to enter; a sill.An entranceThe start of the landing area of a runwayThe quantitative point at which an action is triggered, especially a lower limitThe wage or salary at which income tax becomes dueThe outset of an action or projectThe point where one mentally or physically is vulnerable in response to provocation or to particular things in general. As in emotions, stress, or pain.
Example sentence: Luck is everything... My good luck in life was to be a really frightened person. I'm fortunate to be a coward, to have a low threshold of fear, because a hero couldn't make a good suspense film.