Flat applies to surfaces without curves, protuberances, or indentations: a flat rock.Verb leveled, leveling, levels, or levelled levelling verb transitive.

(at) to bring people or things to an equal rank, condition, etc.: usually with down or up Informal to be frank and honest ( with someone) level Idioms find one's level to reach one's (or its) proper or natural place according to one's (or its).To aim a weapon horizontally.A relative degree, as of achievement, intensity, or concentration: an unsafe level of toxicity; a high level of frustration.

A floor of a multi- storey building.A distance relative to a given reference elevation.