Even; flat; having no part higher than another; having, or
conforming to, the curvature which belongs to the undisturbed liquid
parts of the earth’s surface; as, a level field; level ground; the
level surface of a pond or lake.

Coinciding or parallel with the plane of the horizon;
horizontal; as, the telescope is now level.

A uniform or average height; a normal plane or altitude; a
condition conformable to natural law or which will secure a level
surface; as, moving fluids seek a level.

A horizontal passage, drift, or adit, in a mine.

An instrument by which to find a horizontal line, or adjust
something with reference to a horizontal line.

Hence, figuratively, a certain position, rank, standard,
degree, quality, character, etc., conceived of as in one of several
planes of different elevation.

A horizontal line or plane; that is, a straight line or a
plane which is tangent to a true level at a given point and hence
parallel to the horizon at that point; – this is the apparent level at
the given point.

A line or surface to which, at every point, a vertical or
plumb line is perpendicular; a line or surface which is everywhere
parallel to the surface of still water; – this is the true level, and
is a curve or surface in which all points are equally distant from the
center of the earth, or rather would be so if the earth were an exact
sphere.

An approximately horizontal line or surface at a certain
degree of altitude, or distance from the center of the earth; as, to
climb from the level of the coast to the level of the plateau and then
descend to the level of the valley or of the sea.

A measurement of the difference of altitude of two points,
by means of a level; as, to take a level.