threshold

oviaukko

reuna

kynnys

tuntemus The bottom-most part of a doorway that one crosses to enter; a sill.
puhekieltä An entrance
The start of the landing area of a runway
puhekieltä The quantitative point at which an action is triggered, especially a lower limit.
The wage or salary at which income tax becomes due
The outset of an action or project
The point where one mentally or physically is vulnerable in response to provocation or to particular things in general. As in emotions, stress, or pain.
The point of beginning or entry

From all the pressure my partner has been through lately, his emotional threshold has suddenly gotten pretty low these days. I can tell because he easily loses it when he is around people or hears about anything to do with his concerns.