[ pleyn ]
/ pleɪn /

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 forms

plain·ly, adverbplain·ness, noun

Can be confused

plain plan plane

Synonym study

10. See homely. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for plainly

British Dictionary definitions for plainly (1 of 2)


/ (pleɪn) /




(intensifier)just plain tired
See also plains

Derived Forms

plainly, adverbplainness, noun

Word Origin for plain

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

British Dictionary definitions for plainly (2 of 2)


/ (pleɪn) /


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

Science definitions for plainly


[ plān ]

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 plainly


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.