at or forming a right angle (to something).
Exactly upright; extending in a straight line toward the centre of the earth, etc.
Independent of or irrelevant to each other; orthogonal.
A line or plane that is perpendicular to another.
A device such as a plumb line that is used in making or marking a perpendicular line.
Having axes that meet each other with right angles.
Having a shape like a rectangle.