threshold
thresh.old \'thresh-.(h)o-ld\ n [ME thresshold, fr. OE threscwald; akin to ON threskjo:ldr t]hreshold, OE threscan to thresh 1: the plank, stone, or piece of timber that lies under a door : SILL)M 2a: GATE, DOOR 2b1: END, BOUNDARY; specif : the end of a runway 2b2: the place or point of entering or beginning : OUTSET 3: the point at which a physiological or psychological effect begins to be produced {~ of consciousness a high renal clearance ~}