thresholds

plural of threshold

The lowermost part of a doorway that one crosses to enter; a sill.
(broadly) An entrance; the door or gate of a house.
(broadly) Any end or boundary.
(figuratively) The outset of something; the point of entry, or the beginning of an action.
The start of the landing area of a runway.
The quantitative point at which an action is triggered, especially a lower limit.
The wage or salary at which income tax becomes due.
The point where one is mentally or physically vulnerable in response to a provocation or to other nuisances.