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

Set them perpendicular to the wall with the trigger end against the vertical surface, or in small spaces, set two traps parallel to the wall, with the triggers facing in either direction, says Owen. —Arricca Elin Sansone, Southern Living, 30 Oct. 2025

For example, in vibrations generated at angles that were perpendicular to the web surface or perpendicular to the threads coming out from the web’s center (like the spokes on a wheel), the stabilimenta did not create noticeable changes on how the vibrations moved. —Laura Baisas, Popular Science, 29 Oct. 2025

Noun

Made almost entirely of water ice, the rings extend out in a startlingly flat plane perpendicular to the planet’s orbital axis. —Tom Hawking, Popular Science, 30 Oct. 2025

In the simulations, the team first found that stabilimenta had no effect on waves from the force of an object landing perpendicular to the web or hitting it from the side toward the center. —Andrea Tamayo, Scientific American, 28 Oct. 2025

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