(1) Extremely steep
"The great perpendicular face of the cliff"
(2) At right angles to the plane of the horizon or a base line
"A vertical camera angle"
"The monument consists of two vertical pillars supporting a horizontal slab"
"Measure the perpendicular height"
(3) Intersecting at or forming right angles
"The axes are perpendicular to each other"
(4) An extremely steep face
(5) A cord from which a metal weight is suspended pointing directly to the earth's center of gravity; used to determine the vertical from a given point
(6) A Gothic style in 14th and 15th century England; characterized by vertical lines and a four-centered (Tudor) arch and fan vaulting
(7) A straight line at right angles to another line