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

Adjust your fit with the sporty lace-up closure, and take advantage of the shoes’ orthotic insoles that support the arch to keep foot fatigue at bay. —Mariana Best, Better Homes & Gardens, 26 Jan. 2026

The cutouts reveal the arch of the foot, while the toe box and heel remain covered. —Karla Rodriguez, Footwear News, 23 Jan. 2026

Verb

Over the remainder of the half, the Broncos committed five turnovers and would have been down by even more at the break if not for a high-arching 3-pointer at the buzzer from Buchanan. —Shaun Goodwin, Idaho Statesman, 31 Jan. 2026

Hold the bridge 3 to 4 inches off the floor — just high enough to avoid arching or straining your lower back. —Dana Santas, CNN Money, 30 Jan. 2026

Adjective

Trump showcased three different arch models of varying sizes at a White House event in October. —Zac Anderson, USA Today, 1 Feb. 2026

The square arch door opened to gleaming black marble floors reflecting golden lanterns and plush seats. —Ishani Desai, Sacbee.com, 31 Jan. 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