Hanging or extending in a right line from any point towards the center of the earth or of gravity, or at right angles with the plane of the horizon.

In geometry, falling directly on another line at right angles. The line A is perpendicular to the line B.

A line falling at right angles on the plane of the horizon, that is, extending from some point in a right line towards the center of the earth or center of gravity, or any body standing in that direction.

In geometry, a line falling at right angles on another line, or making equal angles’ with it on each — side.