PLAIN, a. [L. planus; splendor. Gr. to wander.]

1. Smooth; even; level; flat; without elevations and depressions; not rough; as, plain ground or land; a plain surface. In this sense, in philosophical writings, it is written plane.
2. Open; clear. Our troops beat an army in plain fight and open field. – Felton.
3. Void of ornament; simple; as, a plain dress. Plain without pomp, and rich without a show. – Dryden.
4. Artless; simple; unlearned; without disguise, cunning or affectation; without refinement; as, men of the plainer sort. – Gen. xxv. Bacon. Plain, but pious Christians. Hammond.
5. Artless; simple; unaffected; unembellished; as, a plain tale or narration.
6. Honestly undisguised; open; frank; sincere; unreserved. I will tell you the plain truth. Give me leave to be plain with you. – Bacon.
7. Mere; bare; as, a plain knave or fool. – Shak. Pope.
8. Evident to the understanding; clear; manifest; not obscure; as, plain words or language; a plain difference; a plain argument. It is plain in the history, that Esau was never subject to Jacob. – Locke.
9. Not much varied by modulations; as, a plain song or tune.
10. Not high seasoned; not rich; not luxuriously dressed; as, a plain diet.
11. Not ornamented with figures; as, plain muslin.
12. Not dyed.
13. Not difficult; not embarrassing; as, a plain case in law.
14. Easily seen or discovered; not obscure or difficult to be found; as, a plain road or path. Our course is very plain. – Ps. xxvii. A plain or plane figure, in geometry, is a uniform surface, from every point of whose perimeter right lines may be drawn to every other point in the same. – Encyc. A plain figure, in geometry, is a surface in which, if any two points are taken, the straight line which joins them lies wholly in that surface. A plain angle, is one contained under two lines or surfaces, in contradistinction to a solid angle. – Encyc. A horizontal plain is parallel to the horizon. An inclined plain is any plain inclined to the horizon, by whatever angle.

1. Not obscurely; in a manner to be easily understood.
2. Distinctly; articulately; as, to speak plain. – Mark vii.
3. With simplicity; artlessly; bluntly.

1. Level land; usually, an open field with an even surface, or a surface little varied by inequalities; as, all the plain of Jordan. – Gen. xiii.
2. Field of battle. – Arbuthnot.

To lament or wail. [Not used.] [See Complain.] – Spenser.

To level; to make plain or even on the surface. – Hayward.

1. To lament; to bewail; to complain.
   
   
   [Archaic *** Poetic] Milton.

   We with piteous heart unto you pleyne. Chaucer.

2. To lament] to mourn over; as, to plain a loss.
   
   
   [Archaic *** Poetic] Sir J. Harrington.
3. Without elevations or depressions; flat; level; smooth; even. See Plane.
   
   

   The crooked shall be made straight, and the rough places plain. Isa. xl. 4.

4. In a plain manner; plainly.
   
   
   "To speak short and pleyn." Chaucer. "To tell you plain." Shak.
5. Level land; usually, an open field or a broad stretch of land with an even surface, or a surface little varied by inequalities; as, the plain of Jordan; the American plains, or prairies.
   
   

   Descending fro the mountain into playn. Chaucer.

   Him the Ammonite
   Worshiped in Rabba and her watery plain. Milton.

6. To plane or level] to make plain or even on the surface.
   
   
   [R.]

   We would rake Europe rather, plain the East. Wither.

7. Open; clear; unencumbered; equal; fair.
   
   

   Our troops beat an army in plain fight. Felton.

8. A field of battle.
   
   
   [Obs.] Arbuthnot.

   Lead forth my soldiers to the plain. Shak.

9. To make plain or manifest; to explain.
   
   

   What's dumb in show, I'll plain in speech. Shak.

10. Not intricate or difficult; evident; manifest; obvious; clear; unmistakable.
    
    
    "'T is a plain case." Shak.
11. Void of extraneous beauty or ornament; without conspicious embellishment; not rich; simple.
    
    
    (b)