1.Definition: being on a precise horizontal plane
"A billiard table must be level"
2.Definition: having a surface without slope, tilt in which no part is higher or lower than another
"Acres of level farmland"
3.Definition: not showing abrupt variations
"Spoke in a level voice", "She gave him a level look"
5.Definition: oriented at right angles to the plumb
"The picture is level"