threshold
n. countablen. the point where something starts to happen or change. It can also mean the floor at the entrance of a room or building.
n. the point at which a stimulus is of sufficient intensity to begin to produce a specified effect; also the physical entrance or sill of a doorway.
The company is on the threshold of a new era.
The pilot checked the runway threshold markings to ensure the aircraft touched down at the correct point.
Economists argue that once a country crosses a certain income threshold, the demand for luxury goods increases at a significantly higher rate than the demand for basic necessities.
From Middle English threschwolde, threscholde, from Old English þresċold, þerxold, þrexwold (“doorsill, entryway”), from Proto-Germanic þreskudlaz, þreskūþlijaz, þreskwaþluz, from Proto-Germanic þreskaną, þreskwaną (“to thresh, (originally) to tread”), from Proto-Indo-European terh₁- (“to rub, turn”). Cognate with Low German Drüssel (“threshold”), dialectal German Drischaufel, Drissufle, Trüschübel (“threshold”), Danish tærskel (“threshold”), Norwegian terskel (“threshold”), Swedish tröskel (“threshold”), dialectal Swedish träskvald (“threshold”), Icelandic þröskuldur (“threshold”). Pronunciations such as “thresh-hold” are un-etymological and result from analogy with hold.
Often used with the preposition 'of' when referring to a starting point or limit.