[kleer-uh ns]
  1. the act of clearing.
  2. the distance between two objects; an amount of clear space: The bridge allowed a clearance of 37 feet at mean high water.
  3. a formal authorization permitting access to classified information, documents, etc.
  4. Also called clearance sale. the disposal of merchandise at reduced prices to make room for new goods: He bought the coat for half price at a clearance.
  5. a clear space; a clearing: The house stood in a clearance among the trees.
  6. Banking. an exchange of checks and other commercial paper drawn on members of a clearinghouse, usually effected at a daily meeting of the members.
  7. Machinery. a space between two moving parts, left to avoid clashing or to permit relatively free motion.
  8. the angle between a face of a cutting tool, as a lathe tool, and the work.
  9. Nautical.
    1. the clearing of a ship at a port.
    2. Also called clearance papers.the official papers certifying this.
  10. Medicine/Medical. a test of the excretory function of the kidneys based on the volume of blood that is cleared of a specific substance per minute by renal excretion.

Origin of clearance

First recorded in 1555–65; clear + -ance
Related formsclear·er, nounnon·clear·ance, nounpre·clear·ance, noun, adjectiveself-clear·ance, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for self-clearance


    1. the process or an instance of clearingslum clearance
    2. (as modifier)a clearance order
  1. space between two parts in motion or in relative motion
  2. permission for an aircraft, ship, passengers, etc, to proceed
  3. official permission to have access to secret information, projects, areas, etc
  4. banking the exchange of commercial documents drawn on the members of a clearing house
    1. the disposal of merchandise at reduced prices
    2. (as modifier)a clearance sale
  5. sport
    1. the act of hitting or kicking a ball out of the defensive area, as in football
    2. an instance of this
  6. the act of clearing an area of land of its inhabitants by mass evictionSee Highland Clearances
  7. dentistry the extraction of all of a person's teeth
  8. a less common word for clearing
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for self-clearance



1560s, "action of clearing," from clear (v.) + -ance. Meaning "a clear space" is from 1788. Meaning "approval, permission" (especially to land or take off an aircraft) is from 1944, American English; national security sense recorded from 1948. Clearance sale attested by 1843.

Online Etymology Dictionary, © 2010 Douglas Harper

self-clearance in Medicine


  1. The removal of a substance from the blood, expressed as the volume of blood or plasma cleared of the substance per unit time.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.