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.

Open; clear. Our troops beat an army in plain fight and open field.

Void of ornament; simple; as a plain dress. Plain without pomp, and rich without a show.

Artless; simple; unlearned; without disguise, cunning or affectation; without refinement; as men of the plainer sort. Genesis 25:27. Plain but pious christians-- .

Artless; simple; unaffected; unembellished; as a plain tale or narration.

Honestly undisguised; open; frank; sincere; unreserved. I will tell you the plain truth. Give me leave to be plain with you.

Mere; bare; as a plain knave or fool.

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.

Not much varied by modulations; as a plain song or tune.

Not high seasoned; not rich; not luxuriously dressed; as a plain diet.

Not ornamented with figures; as plain muslin.

Not dyed.

Not difficult; not embarrassing; as a plain case in law.

Easily seen or discovered; not obscure or difficult to be found; as a plain road or path. Our coarse is very plain. Psalm 27:11. 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. 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.

Not obscurely; in a manner to be easily understood.

Distinctly; articulately; as, to speak plain. Mark 7:35.

With simplicity; artlessly; bluntly.

Level land; usually, an open field with an even surface, or a surface little varied by inequalities; as all the plain of Jordan. Genesis 13:10-11.

Field of battle.

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