adjective, plain·er, plain·est.


clearly and simply: He's just plain stupid.


an area of land not significantly higher than adjacent areas and with relatively minor differences in elevation, commonly less than 500 feet (150 meters), within the area.
The Plains. Great Plains.

Origin of plain

1250–1300; Middle English (adj., adv., and noun) < Old French (adj. and noun) < Latin plānus flat, level, plānum flat country
Related formsplain·ly, adverbplain·ness, noun
Can be confusedplain plan plane

Synonym study

10. See homely.

Synonyms for plain

Antonyms for plain

1. indistinct. 2. obscure. 13. hilly.



verb (used without object) British Dialect.

to complain.

Origin of plain

1250–1300; Middle English plei(g)nen < Old French plaign-, stem of plaindre < Latin plangere to beat (the breast, etc.), lament; akin to Greek plḗssein to strike Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for plain

Contemporary Examples of plain

Historical Examples of plain

  • The track was plain enough, and there were hamlets at long intervals.

    The Armourer's Prentices

    Charlotte M. Yonge

  • A plain case, that he had left his curiosity with me, and designed to shew me no other.

    Clarissa, Volume 1 (of 9)

    Samuel Richardson

  • Aye, lad, and the plain things are always the hardest things to do.

  • It's a shirt and a plain stocking were got off a drowned man in Donegal.

  • One thing is plain, you must either go to them, or unlock the cellar-door.

    Weighed and Wanting

    George MacDonald

British Dictionary definitions for plain




flat or smooth; level
not complicated; clearthe plain truth
not difficult; simple or easya plain task
honest or straightforward
lowly, esp in social rank or education
without adornment or showa plain coat
(of fabric) without pattern or of simple untwilled weave
not attractive
not mixed; simpleplain vodka
knitting of or done in plain


a level or almost level tract of country, esp an extensive treeless region
a simple stitch in knitting made by putting the right needle into a loop on the left needle, passing the wool round the right needle, and pulling it through the loop, thus forming a new loop
(in billiards)
  1. the unmarked white ball, as distinguished from the spot balls
  2. the player using this ball
(in Ireland) short for plain porter, a light portertwo pints of plain, please


(intensifier)just plain tired
See also plains
Derived Formsplainly, adverbplainness, noun

Word Origin for plain

C13: from Old French: simple, from Latin plānus level, distinct, clear




a dialect or poetic word for complain

Word Origin for plain

C14 pleignen, from Old French plaindre to lament, from Latin plangere to beat
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 plain

c.1300, "flat, smooth," from Old French plain "flat, smooth, even" (12c.), from Latin planus "flat, even, level" (see plane (n.1)). Sense of "evident" is from, c.1300; that of "free from obstruction" is early 14c.; meaning "simple, sincere, ordinary" is recorded from late 14c., especially of dress, "unembellished, without decoration."

In reference to the dress and speech of Quakers, it is recorded from 1824; of Amish and Mennonites, from 1894 (in the Dutch regions of Pennsylvania Plain with the capital is shorthand adjective for "Amish and Old Order Mennonite"). Of appearance, as a euphemism for "ill-favored, ugly" it dates from 1749. Of envelopes from 1913. As an adverb from early 14c. Plain English is from c.1500. Plain dealer "one who deals plainly or speaks candidly" is from 1570s, marked "Now rare" in OED 2nd edition. To be as plain as the nose on (one's) face is from 1690s.


"level country," c.1300 (in reference to Salisbury Plain), from Old French plain "open countryside," from Latin planum "level ground, plain," noun use of neuter of planus (adj.) "flat, even, level" (see plane (n.1)). Latin planum was used for "level ground" but much more common was campus.

Online Etymology Dictionary, © 2010 Douglas Harper

plain in Science



An extensive, relatively level area of land. Plains are present on all continents except Antarctica and are most often located in the interior regions. Because they can occur at almost any altitude or latitude, plains can be humid and forested, semiarid and grass-covered, or arid.
A broad, level expanse, such as an area of the sea floor or a lunar mare.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Idioms and Phrases with plain


In addition to the idioms beginning with plain

  • plain as day
  • plain sailing

also see:

  • in plain English
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.