from The American Heritage® Dictionary of the English Language, 4th Edition

  • adj. Mathematics Intersecting at or forming right angles.
  • adj. Being at right angles to the horizontal; vertical. See Synonyms at vertical.
  • adj. Of or relating to a style of English Gothic architecture of the 14th and 15th centuries, characterized by emphasis of the vertical element.
  • adv. In a perpendicular position.
  • n. Mathematics A line or plane perpendicular to a given line or plane.
  • n. A perpendicular position.
  • n. A device, such as a plumb line, used in marking the vertical from a given point.
  • n. A vertical or nearly vertical line or plane.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. At or forming a right angle (to).
  • n. A line or plane that is perpendicular to another.
  • n. A device such as a plumb line that is used in making or marking a perpendicular line.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Exactly upright or vertical; pointing to the zenith; at right angles to the plane of the horizon; extending in a right line from any point toward the center of the earth.
  • adj. At right angles to a given line or surface.
  • n. A line at right angles to the plane of the horizon; a vertical line or direction.
  • n. A line or plane falling at right angles on another line or surface, or making equal angles with it on each side.

from The Century Dictionary and Cyclopedia

  • Perfectly vertical; at right angles with the plane of the horizon; passing (if extended through the center of the earth; coinciding with the direction of gravity.
  • In geometry, meeting a given line or surface (to which it is said to be perpendicular) at right angles.
  • In zoology, forming a right angle with the longitudinal or latitudinal axis of the body: as, a perpendicular head; epimeron perpendicular, etc.
  • n. A line at right angles to the plane of the horizon; a line that coincides in direction with a radius of the earth or with the direction of gravity.
  • n. 2. In geometry, a line that meets another line or a place at right angles, or makes equal angles with it on every side.
  • n. In gunnery, a small instrument for finding the center-line of a piece of ordnance, in the operation of pointing it at an object; a gunner's level.
  • n. In ship-building, one of the three conventional lines perpendicular to the line of the keel, used as reference lines from which measurements in the fore-and-aft direction are taken.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. a straight line at right angles to another line
  • n. a cord from which a metal weight is suspended pointing directly to the earth's center of gravity; used to determine the vertical from a given point
  • adj. at right angles to the plane of the horizon or a base line
  • adj. intersecting at or forming right angles
  • n. a Gothic style in 14th and 15th century England; characterized by vertical lines and a four-centered (Tudor) arch and fan vaulting
  • n. an extremely steep face
  • adj. extremely steep


Middle English perpendiculer, from Old French, from Latin perpendiculāris, from perpendiculum, plumb line, from perpendere, to weigh carefully : per-, per- + pendere, to weigh.
(American Heritage® Dictionary of the English Language, Fourth Edition)
Latin perpendiculum ("plumb line"). (Wiktionary)



Log in or sign up to get involved in the conversation. It's quick and easy.

  • Sounds like a great Wordie upbringing, or wordolesence.

    February 13, 2008

  • This is the 1st "big" word my dad taught me.
    I would sit up on his work bench and watch him making jigs and tying flies for his fishing hobby. Instead of attempting conversation with a child he would grill me on words and I would have to parrot them back with their meanings for later exhibition in front of "company." Upon reflection, kind of odd but I loved it and I still love words. So, thanks, Dad.

    February 10, 2008