thresh·old (thr?sh??ld?, -h?ld?)n.1. A piece of wood or stone placed beneath a door; a doorsill.2. Either end of an airport runway.3. The place or point of beginning; the outset: on the threshold of a new era.4. The point that must be exceeded to begin producing a given effect or result or to elicit a response: a low threshold of pain.[Middle English thresshold, from Old English therscold, threscold; see ter?- in Indo-European roots.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.threshold (??r????ld; ??r???h??ld) n1. (Building) Also called: doorsill a sill, esp one made of stone or hardwood, placed at a doorway2. any doorway or entrance3. the starting point of an experience, event, or venture: on the threshold of manhood. 4. (Psychology) psychol the strength at which a stimulus is just perceived: the threshold of consciousness. Compare absolute threshold, difference threshold5. a. a level or point at which something would happen, would cease to happen, or would take effect, become true, etcb. (as modifier): threshold price; threshold effect. 6. (General Physics) a. the minimum intensity or value of a signal, etc, that will produce a response or specified effect: a frequency threshold. b. (as modifier): a threshold current. 7. (Industrial Relations & HR Terms) (modifier) designating or relating to a pay agreement, clause, etc, that raises wages to compensate for increases in the cost of living[Old English therscold; related to Old Norse threskoldr, Old High German driscubli, Old Swedish thriskuldi]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014thresh?old (??r?? o?ld, ??r?? ho?ld) n. 1. the sill of a doorway. 2. the entrance to a house or building. 3. any point of entering or beginning: the threshold of a new career. 4. Also called limen. the point at which a stimulus is of sufficient intensity to begin to produce an effect: the threshold of consciousness; a low threshold of pain. [before 900; Middle English; Old English threscold, threscwald, c. Old Norse thresk?ldr; akin to thresh in old sense ?trample, tread?; -old, -wald unexplained] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.thresholdThe beginning of that portion of the runway usable for landing.Dictionary of Military and Associated Terms. US Department of Defense 2005.