Definitions
1.AdjectiveAt or forming a right angle (to something)."In most houses, the walls are perpendicular to the floor."
2.AdjectiveExactly upright; extending in a straight line toward the centre of the earth, etc.
3.AdjectiveIndependent of or irrelevant to each other; orthogonal.
4.NounA line or plane that is perpendicular to another.
5.NounA device such as a plumb line that is used in making or marking a perpendicular line.
6.NounA meal eaten at a tavern bar while standing up.