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 capitalized : 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

Adjective

• erect
• plumb
• raised
• stand-up
• standing
• upright
• upstanding
• vertical

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

Dragonflies hold their wings perpendicular to their bodies, while a damselfly’s wings point straight back, parallel to its body. —Carl R. Gold, Baltimore Sun, 8 June 2025

The action moves from the scarred beach to a quarry where a rock wall is detonated, to liberate mighty boulders of granite that will eventually be placed perpendicular to the shoreline, reaching out into the ocean. —Richard Brody, New Yorker, 13 May 2025

Noun

One of those was Cheryl Petersen, who lives on Newberry, a street perpendicular to 31st. —Jesse Wright, Chicago Tribune, 9 June 2025

The international research team fabricated a solid-state gallium arsenide (GaAs) quantum well, which is a thin layer of material that confines particles such as electrons or holes in the dimension perpendicular to the layer surface. —IEEE Spectrum, 18 Dec. 2017

Word History

Etymology

Adjective

Middle English perpendiculer, from Middle French, from Latin perpendicularis, from perpendiculum plumb line, from per- + pendēre to hang — more at pendant

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