PERPENDICULAR
\pˌɜːpəndˈɪkjʊlə], \pˌɜːpəndˈɪkjʊlə], \p_ˌɜː_p_ə_n_d_ˈɪ_k_j_ʊ_l_ə]\
Definitions of PERPENDICULAR
 2006  WordNet 3.0
 2011  English Dictionary Database
 2010  New Age Dictionary Database
 1913  Webster's Revised Unabridged Dictionary
 1919  The Winston Simplified Dictionary
 1919  The Concise Standard Dictionary of the English Language
 1899  The american dictionary of the english language.
 1894  The Clarendon dictionary
 1871  The Cabinet Dictionary of the English Language
Sort: Oldest first

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

a straight line at right angles to another line

extremely steep; "the great perpendicular face of the cliff"

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"

a Gothic style in 14th and 15th century England; characterized by vertical lines and a fourcentered (Tudor) arch and fan vaulting
By Princeton University

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

a straight line at right angles to another line

extremely steep; "the great perpendicular face of the cliff"

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"
By DataStellar Co., Ltd

Exactly upright or vertical; pointing to the zenith; at right angles to the plane of the horizon; extending in a right line from any point toward the center of the earth.

At right angles to a given line or surface; as, the line ad is perpendicular to the line bc.

A line at right angles to the plane of the horizon; a vertical line or direction.

A line or plane falling at right angles on another line or surface, or making equal angles with it on each side.
By Oddity Software

Exactly upright or vertical; pointing to the zenith; at right angles to the plane of the horizon; extending in a right line from any point toward the center of the earth.

At right angles to a given line or surface; as, the line ad is perpendicular to the line bc.

A line at right angles to the plane of the horizon; a vertical line or direction.

A line or plane falling at right angles on another line or surface, or making equal angles with it on each side.
By Noah Webster.

At right angles to a line or surface; upright.

An upright line; a line at right angles with another.

Perpendicularity.
By William Dodge Lewis, Edgar Arthur Singer
By James Champlin Fernald

Exactly upright: extending in a straight line toward the centre of the earth: (geom.) at right angles to a given line or surface.

A perpendicular line or plane.
By Daniel Lyons
By William Hand Browne, Samuel Stehman Haldeman