- level [lev′əl]n.[OFr livel < VL * libellus < L libella, dim. of libra, a balance, level, weight]1. an instrument for determining, or adjusting a surface to, an even horizontal plane: it has a glass tube partly filled with liquid so as to leave an air bubble that moves to the exact center of the tube when the instrument is on an even horizontal plane; often there is another such tube which indicates when the instrument is perpendicular to the horizontal2.a) SURVEYOR'S LEVELb) a measuring of differences in elevation with this instrument3.a) a horizontal plane or line; esp., such a plane taken as a basis for the measurement of elevation [sea level]b) the height, or altitude, of such a plane4. a relatively flat and even area of land or other surface; horizontal area5. the same horizontal plane [to keep the tops of pictures on a level]6. usual or normal position with reference to a certain height [water seeks its level]7. position, elevation, or rank considered as one of the planes in a scale of values [levels of income]8. a horizontal drift or gallery in a mine9. the degree of concentration of a substance in a fluid10. Physics the ratio of a quantity's magnitude to an arbitrarily selected magnitudeadj.1. having no part higher than any other; perfectly flat and even; conforming to the surface of still water2. conforming to the plane of the horizon; not sloping3. being of the same height or being in the same plane; even (with)4. even with the top of the container; not heaping [a level teaspoonful]5.a) equal in importance, rank, degree, etc.b) conforming to a specified level or rank [high-level talks]c) equally advanced in developmentd) even or uniform in tone, color, pitch, volume, rate, etc.6.a) not having or showing sudden differences or inequalities; well-balanced; equableb) not excited or disturbed; calm or steady7. paid or to be paid in equal amounts over a period of time☆ 8. Slang honest; straightadv.Now Rare on a level linevt.leveled or levelled, leveling or levelling1. to make level; specif.,a) to make perfectly horizontal by means of a levelb) to make flat and evenc) to equalize in height, rank, quality, etc.: often with down or upd) to make even in tone, color, pitch, etc.2. to knock to the ground; demolish; lay low [the storm leveled the tree]3. to aim (a gun, etc.) for firing4. to aim or direct5. Surveying to determine the differences in altitude in (a plot of ground)vi.1. to aim a gun, etc. (at)2. to bring people or things to an equal rank, condition, etc.: usually with down or up☆ 3. Slang to be frank and honest ( with someone)——————find one's level or find its levelto reach one's proper or natural place according to one's qualities, capacity, etc.——————level off1. to make flat and even2. to become horizontal, as an airplane in flight: also level out3. to become stable or constant——————one's level bestInformal the best one can do——————☆ on the levelSlang honest(ly) and fair(ly)levellyadv.levelnessn.SYN.- LEVEL is applied to a surface that is parallel to, or conforms with, the horizon; FLAT1 implies the absence to any marked degree of depressions or elevations in a surface, in whatever direction it lies; PLANE2 describes a real or imaginary surface that is absolutely flat and wholly contains every straight line joining any two points lying in it; EVEN1 is applied to a surface that is uniformly level or flat, or to a surface that is in the same plane with, or in a plane parallel to, another; a SMOOTH surface has no roughness or projections, often as a result of wear, planing, polishing, etc.
English World dictionary. V. Neufeldt. 2014.