arch

1 of 9

noun

ˈärch 

1

: a typically curved structural member spanning an opening and serving as a support (as for the wall or other weight above the opening)

2

a

: something resembling an arch in form or function

especially : either of two vaulted portions of the bony structure of the foot that impart elasticity to it

b

: something that has a curved shape like an arch

There was a slight arch in her eyebrows.

an arch in the cat's back

3

: archway

Illustration of arch

• 1 round
• imp impost
• sp springer
• v voussoir
• k keystone
• ext extrados
• int intrados
• 2 horseshoe
• 3 lancet
• 4 ogee
• 5 trefoil
• 6 basket-handle
• 7 Tudor

arch

2 of 9

verb

arched; arching; arches

transitive verb

1

: to cover or provide with an arch

A bridge arches the stream.

2

: to form into an arch

She arched her eyebrows.

intransitive verb

1

: to form an arch

Trees arch above the promenade.

2

: to take an arch-shaped course

The ball arched toward the basket.

arch

3 of 9

adjective

1

: principal, chief

your arch opponent/rival

an arch enemy

2

a

: mischievous, saucy

b

: marked by a deliberate and often forced playfulness, irony, or impudence

known for her arch comments

… decided to answer them by being teacherly in a sort of arch, Olympian way.

—Gerald Early

archness noun

arch

4 of 9

abbreviation (1)

1

archaic

2

archery

3

architect; architectural; architecture

Arch

5 of 9

abbreviation (2)

Archbishop

arch-

6 of 9

prefix (1)

1

: chief : principal

archfiend

2

: extreme : most fully embodying the qualities of the kind

archconservative

arch-

7 of 9

prefix (2)

see archi-

-arch

8 of 9

noun combining form

: ruler : leader

matriarch

-arch

9 of 9

adjective combining form

: having (such) a point or (so many) points of origin

endarch

Did you know?

As a prefix, arch- appears in a number of titles referring to positions of superiority, such as archduke and archbishop; it can also mean "chief" (as in archnemesis) or "extreme" (archconservative). It comes from the Greek verb archein, meaning "to begin or to rule."

Synonyms of arch

Noun

• curvature
• curve
• angle
• bend
• turn
• bow

Verb

• bend
• curve
• hook
• bow
• curl

Adjective

• main
• highest
• primary
• greatest
• dominant
• predominant
• big
• foremost
• leading
• central

Examples of arch in a Sentence

Noun

There was a slight arch to her eyebrows.

an arch in the cat's back

Verb

The cat arched its back.

She arched her eyebrows in surprise.

A tree arches over the road.

She arched backward to begin the exercise.

Adjective

a politician known for his arch humor

The novel is never mocking or arch in its tone.

Recent Examples on the Web

Noun

Multiple speakers, including some with family members in the cemetery, cited a Washington Post analysis that the arch would cast shadows on thousands of graves. — Arkansas Online, 6 Nov. 2026

Judge Chutkan agreed that the local governments are likely to be harmed by the construction of the arch. — News Desk, Artforum, 6 Nov. 2026

Verb

The painting is commanded by an umbrella pine, which arches high into the butter-yellow heavens, on the right, leaning over the heart of the composition. — Anthony Lane, New Yorker, 5 Nov. 2026

The work consists of a transparent female figure, sculpted with her back arched in a bridge position and filled halfway with water. — Shanti Escalante-De Mattei, ARTnews.com, 26 Oct. 2026

Adjective

Critics say the arch lacks required congressional approval and could disrupt traffic and emergency response; the administration argues a century-old law authorizes the memorial. — Will Weissert, Los Angeles Times, 6 Nov. 2026

The arch dispute adds to a broader debate over the Administration’s frequent use of national security to justify its policies. — Rebecca Schneid, Time, 31 Oct. 2026

Word History

Etymology

Noun and Verb

Middle English arche, from Anglo-French, from Vulgar Latin *arca, from Latin arcus — more at arrow

Adjective

arch- entry 1

Prefix (1)

Middle English arche-, arch-, from Old English & Anglo-French; Old English arce-, from Late Latin arch- & Latin archi-; Anglo-French arch-, from Late Latin arch- & Latin archi-, from Greek arch-, archi-, from archein to begin, rule; akin to Greek archē beginning, rule, archos ruler

Noun combining form

Middle English -arche, from Anglo-French & Late Latin & Latin; Anglo-French -arche, from Late Latin -archa, from Latin -arches, -archus, from Greek -archēs, -archos, from archein

Adjective combining form

probably from German, from Greek archē beginning

First Known Use

Noun

13th century, in the meaning defined at sense 2a

Verb

15th century, in the meaning defined at transitive sense 1

Adjective

1547, in the meaning defined at sense 1

Phrases Containing arch

• aortic arch
• arch of the aorta
• gill arch
• Gothic arch
• horseshoe arch
• lancet arch
• neural arch
• proscenium arch
• Tudor arch
• vertebral arch
• zygomatic arch

Rhymes for arch

• arch
• march
• starch
• cornstarch

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Kids Definition

arch

1 of 4 noun

ˈärch 

1

: a usually curved part of a structure that is over an opening and serves as a support

2

: something resembling an arch in form or function

especially : either of two portions of the bony structure of the foot that give it flexibility

3

: archway

arch

2 of 4 verb

1

: to cover or provide with an arch

2

: to form into an arch

3

: to take an arch-shaped path

arch

3 of 4 adjective

1

: principal, chief

an arch opponent

2

: being clever and mischievous

an arch look

archly adverb

archness noun

arch-

4 of 4 prefix

: chief : principal

archenemy

Etymology

Noun

Middle English arche "arch," from early French arche (same meaning), derived from Latin arcus "bow (weapon)"

Adjective

from arch- (prefix)

Prefix

derived from Greek archein "to begin, rule"

Medical Definition

arch

noun

ˈärch 

1

: an anatomical structure that resembles an arch in form or function: as

a

: either of two vaulted portions of the bony structure of the foot that impart elasticity to it:

(1)

: a longitudinal arch supported posteriorly by the basal tuberosity of the calcaneus and anteriorly by the heads of the metatarsal bones

(2)

: a transverse arch consisting of the metatarsals and first row of tarsals and resulting from elevation of the central anterior portion of the median longitudinal arch

b

: arch of the aorta

2

: a fingerprint in which all the ridges run from side to side and make no backward turn