perpendicular
per-pen-dic-u-lar
noun
A line or plane that is at right angles to another line, plane, or surface.
"Draw a perpendicular from the point to the line."
adjective
At an angle of 90 degrees to a given line, plane, or surface.
"The wall is perpendicular to the floor."
Thesaurus
Synonyms: plumb line, upended, plumb, vertical, upright, unsloped, right, rectangular, orthogonal, normal, English-Gothic, perpendicular style
Antonyms: horizontal, inclined, oblique, parallel