Definition of: threshold

(thresh′ōld, -hōld) noun
1. The plank, timber, or stone lying under the door of a building; doorsill.
2. The entrance, entering point, or beginning of anything: the threshold of the 20th century.
3. Physiol. The point at which a stimulus, as of a nerve or muscle, just produces a response; especially, the minimum degree of stimulation necessary for conscious perception: the threshold of consciousness: also called limen. ♦ Collateral adjective: liminal. [OE therscold]