perpendicular

1 of 2

adjective

per·​pen·​dic·​u·​lar ˌpər-pən-ˈdi-kyə-lər 

1

a

: standing at right angles to the plane of the horizon : exactly upright

b

: being at right angles to a given line or plane

2

: extremely steep : precipitous

3

often Perpendicular : of or relating to a medieval English Gothic style of architecture in which vertical lines predominate

4

: relating to, uniting, or consisting of individuals of dissimilar type or on different levels

perpendicularity

ˌpər-pən-ˌdi-kyə-ˈler-ə-tē 

-ˈla-rə-

noun

perpendicularly

ˌpər-pən-ˈdi-kyə-lər-lē 

adverb

perpendicular

2 of 2

noun

: a line at right angles to a line or plane (as of the horizon)

Synonyms of perpendicular

Adjective

• vertical
• standing
• erect

Choose the Right Synonym for perpendicular

vertical, perpendicular, plumb mean being at right angles to a base line.

vertical suggests a line or direction rising straight upward toward a zenith.

the side of the cliff is almost vertical

perpendicular may stress the straightness of a line making a right angle with any other line, not necessarily a horizontal one.

the parallel bars are perpendicular to the support posts

plumb stresses an exact verticality determined (as with a plumb line) by earth's gravity.

make sure that the wall is plumb

Examples of perpendicular in a Sentence

Adjective

She lives on the street that is perpendicular to mine.

river rafters staring awestruck at the canyon's nearly perpendicular cliffs

Recent Examples on the Web

Adjective

Vonn tried to twist and regain her balance in mid-air but landed awkwardly with her skis perpendicular to the fall line, ensuring a brutal fall. —Andrew Dampf, Denver Post, 8 Feb. 2026

If the lever is perpendicular to the gas line, the gas valve is shut off. —Timothy Dale, The Spruce, 28 Jan. 2026

Noun

The racer is traversing the hill perpendicular to the fall line, almost moving in an upward direction. —Los Angeles Times, 9 Feb. 2026

When crossing intersections, ride perpendicular to tram lines, as bike tires can easily get stuck in them, sending even the most experienced riders flying over the handlebars. —Georgina Ustik, Condé Nast Traveler, 5 Feb. 2026

Word History

Etymology

Adjective

Middle English perpendiculer, borrowed from Middle French & Latin; Middle French perpendiculier, borrowed from Latin perpendiculāris, from perpendiculum "plumb line, vertical line or plane" (from perpendere "to weigh with care, poise, balance carefully" + -i-culum, instrumental suffix —going back to Indo-European *-tlom) + -āris -ar — more at perpend

Noun

derivative of perpendicular entry 1

First Known Use

Adjective

14th century, in the meaning defined at sense 1a

Noun

1551, in the meaning defined above

Rhymes for perpendicular

• appendicular
• canalicular
• diverticular
• suborbicular
• acicular
• articular
• curricular
• cuticular
• funicular
• lenticular
• navicular
• particular

Kids Definition

perpendicular

1 of 2 adjective

per·​pen·​dic·​u·​lar ˌpər-pən-ˈdik-yə-lər 

1

: exactly vertical or upright

2

: forming a right angle with each other or with a given line or plane

perpendicularly adverb

perpendicular

2 of 2 noun

: a perpendicular line

Etymology

Adjective

Middle English perpendiculer "exactly upright," from early French perpendiculer (same meaning), from Latin perpendicularis (same meaning), derived from per- "thoroughly" and pendēre "to hang" — related to depend, pendulum