perpendicular

adj. vertical; plumb, upright

n. vertical line; plumb, instrument used to set a vertical line

In geometry, two lines or planes (or a line and a plane), are considered perpendicular (or orthogonal) to each other if they form congruent adjacent angles. The term may be used as a noun or adjective. Thus, referring to Figure 1, the line AB is the perpendicular to CD through the point B.If a line is bending to another as in Figure 1, all of the angles created by their intersection are called right angles (right angles measure ½π radians, or 90°). Conversely, any lines that meet to form right angles are perpendicular. The line AB does not have to end at B to be considered perpendicular.
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Noun
1. a straight line at right angles to another line
(hypernym) straight line
2. a Gothic style in 14th and 15th century England; characterized by vertical lines and a four-centered (Tudor) arch and fan vaulting
(synonym) perpendicular style, English-Gothic, English-Gothic architecture
(hypernym) Gothic, Gothic architecture
(hyponym) Tudor architecture
3. 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
(synonym) plumb line
(hypernym) cord
(hyponym) lead line, sounding line
(part-meronym) plumb bob, plumb, plummet
4. an extremely steep face
(hypernym) face
Adjective
1. intersecting at or forming right angles; "the axes are perpendicular to each other"
(antonym) oblique
(similar) normal
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"
(synonym) vertical
(similar) plumb
(see-also) steep
(attribute) orientation
3. extremely steep; "the great perpendicular face of the cliff"
(similar) steep

adj. up and down; perpendicular

n. perpendicular, vertical line

n. normal, perpendicular; taproot