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
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
arched; arching; arches
1
: to cover or provide with an arch
A bridge arches the stream.
2
: to form into an arch
She arched her eyebrows.
1
: to form an arch
Trees arch above the promenade.
2
: to take an arch-shaped course
The ball arched toward the basket.
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
Gerald Early
archness
noun
1
: chief : principal
archfiend
2
: extreme : most fully embodying the qualities of the kind
archconservative
see archi-
: ruler : leader
matriarch
: 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."
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
Daryl Austin, USA Today, 15 Dec. 2025
The rear wheel arches of the Geely EX5 prototype appear to have been enlarged to accommodate rims capable of rotating 90 degrees, which could noticeably reduce interior space.
—Bojan Stojkovski, Interesting Engineering, 13 Dec. 2025
New Atlas, 13 Dec. 2025
Lift one leg straight back behind you without arching your back.
—Rikkilynn Shields Hannigan, Health, 11 Dec. 2025
Rachel Davies, Architectural Digest, 16 Dec. 2025
The key constitutional context Many commentators have highlighted the stark polarization of this election, with a Communist Party labor minister campaigning against the arch-conservative Kast, who has lauded the Pinochet dictatorship under which his deceased older brother once served.
—Andra B. Chastain, The Conversation, 15 Dec. 2025
See All Example Sentences for arch
Examples are automatically compiled from online sources to
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Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
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Noun
Flat feet may strain tissues along the arch, while high arches may overload the ball of the foot.
—Daryl Austin, USA Today, 15 Dec. 2025
The rear wheel arches of the Geely EX5 prototype appear to have been enlarged to accommodate rims capable of rotating 90 degrees, which could noticeably reduce interior space.
—Bojan Stojkovski, Interesting Engineering, 13 Dec. 2025
Verb
Note, however, the Vision XL is also essentially one big 10-in-tall block with a completely flat roof, whereas some hardshell RTTs, including the Skycamp, have roof designs with a high point that arches down toward the front and/or back.
—New Atlas, 13 Dec. 2025
Lift one leg straight back behind you without arching your back.
—Rikkilynn Shields Hannigan, Health, 11 Dec. 2025
Adjective
Designer Jerry Lorenzo doesn’t much care for outré gestures, theatrical poses, and arch style statements redolent of novelty.
—Rachel Davies, Architectural Digest, 16 Dec. 2025
The key constitutional context Many commentators have highlighted the stark polarization of this election, with a Communist Party labor minister campaigning against the arch-conservative Kast, who has lauded the Pinochet dictatorship under which his deceased older brother once served.
—Andra B. Chastain, The Conversation, 15 Dec. 2025
See All Example Sentences for arch
Cite this Entry
“Arch.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/arch. Accessed 21 Dec. 2025.
Copy CitationKids Definition
arch
2 of 4 verb1
: to cover or provide with an arch
2
: to form into an arch
3
: to take an arch-shaped path
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
noun1
: 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
2
: a fingerprint in which all the ridges run from side to side and make no backward turn
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