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  1. a flat or level surface.
  2. Geometry. a surface generated by a straight line moving at a constant velocity with respect to a fixed point.
  3. Fine Arts. an area of a two-dimensional surface having determinate extension and spatial direction or position: oblique plane; horizontal plane.
  4. a level of dignity, character, existence, development, or the like: a high moral plane.
  5. Aeronautics.
    1. an airplane or a hydroplane: to take a plane to Dallas.
    2. a thin, flat or curved, extended section of an airplane or a hydroplane, affording a supporting surface.
  6. Architecture. a longitudinal section through the axis of a column.
  1. flat or level, as a surface.
  2. of or relating to planes or plane figures.
verb (used without object), planed, plan·ing.
  1. to glide or soar.
  2. (of a boat) to rise partly out of the water when moving at high speed.
  3. Informal. to fly or travel in an airplane: We'll drive to Detroit and plane to Los Angeles.

Origin of plane1

1400–50 for sense “to soar”; 1640–50 for noun and adj. senses; (noun) < Latin plānum flat surface (noun use of plānus flat); (adj.) < Latin plānus; first used to distinguish the geometrical senses formerly belonging to plain1; in def. 5, shortened form of airplane, aeroplane, or hydroplane; (v.) late Middle English planen (of a bird) to soar (compare Middle French planer); akin to plain1
Related formsplane·ness, noun
Can be confusedplain plan plane


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4. stratum, stage. 7. smooth, even, flush.


  1. Carpentry. any of various woodworking instruments for paring, truing, or smoothing, or for forming moldings, chamfers, rabbets, grooves, etc., by means of an inclined, adjustable blade moved along and against the piece being worked.
  2. a trowellike tool for smoothing the surface of clay in a brick mold.
verb (used with object), planed, plan·ing.
  1. to smooth or dress with or as if with a plane or a planer.
  2. to remove by or as if by means of a plane (usually followed by away or off).
verb (used without object), planed, plan·ing.
  1. to work with a plane.
  2. to function as a plane.

Origin of plane2

1275–1325; (noun) Middle English (< Middle French) < Late Latin plāna, derivative of plānāre to smooth, itself derivative of Latin plānus plain1; (v.) Middle English planen (< Middle French planer) < Late Latin plānāre


  1. plane tree.

Origin of plane3

1350–1400; Middle English < Middle French < Latin platanus < Greek plátanos, derivative of platýs broad, flat1 (with reference to the leaves)
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for plane

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British Dictionary definitions for plane


  1. maths a flat surface in which a straight line joining any two of its points lies entirely on that surface
  2. a flat or level surface
  3. a level of existence, performance, attainment, etc
    1. short for aeroplane
    2. a wing or supporting surface of an aircraft or hydroplane
  1. level or flat
  2. maths (of a curve, figure, etc) lying entirely in one plane
verb (intr)
  1. to fly without moving wings or using engines; glide
  2. (of a boat) to rise partly and skim over the water when moving at a certain speed
  3. to travel by aeroplane
Derived Formsplaneness, noun

Word Origin

C17: from Latin plānum level surface


  1. a tool with an adjustable sharpened steel blade set obliquely in a wooden or iron body, for levelling or smoothing timber surfaces, cutting mouldings or grooves, etc
  2. a flat tool, usually metal, for smoothing the surface of clay or plaster in a mould
verb (tr)
  1. to level, smooth, or cut (timber, wooden articles, etc) using a plane or similar tool
  2. (often foll by off) to remove using a plane

Word Origin

C14: via Old French from Late Latin plāna plane, from plānāre to level


  1. See plane tree
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 plane


"flat surface," c.1600, from Latin planum "flat surface, plane, level, plain," noun use of neuter of adjective planus "flat, level, even, plain, clear," from PIE *pla-no- (cf. Lithuanian plonas "thin;" Celtic *lanon "plain;" perhaps also Greek pelanos "sacrificial cake, a mixture offered to the gods, offering (of meal, honey, and oil) poured or spread"), suffixed form of root *pele- (2) "to spread out, broad, flat" (cf. Old Church Slavonic polje "flat land, field," Russian polyi "open;" Old English and Old High German feld, Middle Dutch veld "field"). Introduced (perhaps by influence of French plan in this sense) to differentiate the geometrical senses from plain, which in mid-16c. English also meant "geonetric plane." Figurative sense is attested from 1850. As an adjective from 1660s.


1908, short for aeroplane (see airplane).


"tool for smoothing surfaces," mid-14c., from Old French plane, earlier plaine (14c.), from Late Latin plana, back-formation from planare "make level," from Latin planus "level, flat" (see plane (n.1)).


"tree of the genus Platanus," late 14c., from Old French plane, earlier plasne (14c.), from Latin platanus, from Greek platanos, earlier platanistos "plane tree," a species from Asia Minor, associated with platys "broad" (see plaice (n.)), in reference to its leaves. Applied since 1778 in Scotland and northern England to the sycamore, whose leaves somewhat resemble those of the true plane tree.


"to make smooth," early 14c., "to gloss over, explain away;" mid-14c. as "to make smooth or even," from Old French planer "to smooth, level off; wipe away, erase" (12c.), from Late Latin planare "make level," from Latin planus "level, flat" (see plane (n.1)). In early use in English often plain. Related: Planed; planing.


"soar, glide on motionless wings," early 15c., from Old French planer "to hover (as a bird), to lie flat," from plan (n.) "plane," from Latin planum "flat surface" (see plane (n.1)), on notion of bird gliding with flattened wings. Of boats, etc., "to skim over the surface of water," it is first found 1913. Related: Planed; planing.

Online Etymology Dictionary, © 2010 Douglas Harper

plane in Medicine


  1. A surface containing all the straight lines that connect any two points on it.
  2. A flat or level surface.
  3. An imaginary surface formed by extension through any axis of the body or through two definite points on the body.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

plane in Science


  1. A two-dimensional surface, any two of whose points can be joined by a straight line that lies entirely in the surface.
  1. Lying in a plane:a plane curve.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

plane in Culture


A geometrical location having only two dimensions — length and width (no height). (See coordinates and plane geometry.)

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.