[ 'θrɛʃəʊld , 'θrɛʃˌhəʊld ]
■ noun
1》 a strip of wood or stone forming the bottom of a doorway and crossed in entering a house or room.
2》 a level or point at which something starts or ceases to happen or come into effect.
↘the level at which one starts to feel or react to something: a low pain ~.
Origin
OE therscold , threscold ; first element related to thresh (in the sense 'tread').