plane

level, flat, plane, even, smooth mean having a surface without bends, curves, or irregularities. level applies to a horizontal surface that lies on a line parallel with the horizon.

• • the vast prairies are nearly level

flat applies to a surface devoid of noticeable curvatures, prominences, or depressions.

• • the work surface must be flat

plane applies to any real or imaginary flat surface in which a straight line between any two points on it lies wholly within that surface.

• • the plane sides of a crystal

even applies to a surface that is noticeably flat or level or to a line that is observably straight.

• • trim the hedge so it is even

smooth applies especially to a polished surface free of irregularities.

• • a smooth skating rink