Are "Arc" and "Arch" interchangeable?

Question

I've checked the dictionaries and both words have a common meaning:

arc - a shape or structure resembling an arc.

arch - a curved symmetrical structure spanning an opening and typically supporting the weight of a bridge, roof, or wall above it.

Can both these words be interchangeable?

We went through the arc.
We went through the arch.

JavaLatte · Accepted Answer · 2016-11-28T10:08:25.233

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Here is the Oxford Dictionary definition for arc that you referred to:

arc noun

1A part of a curve, especially a part of the circumference of a circle:
the point where a tangential line touches the arc of a circle

1.1 A shape or structure resembling an arc:
the huge arc of the sky

Note that, although definition 1.1 refers to a structure, the word arc in the following example (and in all of the other examples quoted) if followed by of. arc is not an actual structure: it serves only to define the shape of the real structure (the sky).

The definition in the Oxford dictionary would be better written as

the shape of a structure resembling an arc.

Here are the definitions from the Cambridge dictionary: as you can see, there is no (STRUCTURE) meaning for arc.

arc
noun [ C ] (CURVE) the shape of part of a circle, or other curved line.

arch
noun [ C ] (CURVED STRUCTURE) a structure, consisting of a curved top on two supports, that holds the weight of something above it.
noun [ C ] (SHAPE) something that has the shape of an arch, often used for decoration:

edited Nov 28 '16 at 10:08

answered Nov 28 '16 at 09:43

JavaLatte

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https://en.oxforddictionaries.com/definition/arc – SovereignSun Nov 28 '16 at 09:53
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@SovereignSun I would suggest that usage of arc is rather uncommon and is somewhat metaphorical in comparing the shape of a thing to the shape of a part of a circle - I would encourage you to look at the examples provided on your link. Generally an "arc" will not be understood to be a thing while an "arch" will be. – Nat Nov 28 '16 at 09:59
So they aren't interchangeable? – SovereignSun Nov 28 '16 at 10:04
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They are definitely not interchangeable. – JavaLatte Nov 28 '16 at 10:08
does this mean one could say "an arc of an arch"? (whatever that ends up being xd) – Olle Kelderman Nov 28 '16 at 10:31
Are the words archangel, archaeology, archaic, archbishop somehow connected with the meaning of the word arch? – SovereignSun Nov 28 '16 at 10:38
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@SovereignSun: Archangel and archbishop are from Ancient Greek ἄρχω ‎(árkhō): to lead. Archaeology and archaic are from Ancient Greek αρχαίος ‎(archaíos): ancient. Arch is from Latin arcus : a bow, arc, arch. So no, there is no connection. – TonyK Nov 28 '16 at 11:33
@TonyK what about the words "archtop" and "archetype"? – SovereignSun Nov 28 '16 at 11:50
Archtop (as in "archtop guitar") is indeed derived from arch. As for archetype, you can look that up yourself on Wiktionary. – TonyK Nov 28 '16 at 11:52
There is another definition of Arc i do not see here, The Story arc. It sections off a large/long story into more digestible parts, from the start of a problem/event that drives the story to the conclusion of that part, before starting the next one. Its not used often because there are other natural dividers used at the same time which have other names that we do recognize(like book as in the third book, or season). Its most common use is for some popular Japanese animations (One Piece or Naruto) where there are no seasons, and 100s of episodes following one very long story line. – Ryan Nov 28 '16 at 17:45
Yes @Ryan, there are other definitions of arc, but they are not relevant to an answer for this question. See the Oxford Dictionary link that I provided in my answer for a full list of the definitions, including the one that you refer to. – JavaLatte Nov 28 '16 at 19:05

score 2 · Answer 2 · answered Nov 28 '16 at 12:12

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No. An arch (noun) suggests something that is connected to the ground, like the underside of a bridge or a tunnel. An arc (noun) can be free-floating.

answered Nov 28 '16 at 12:12

Sam

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Do you have a citation for this claim? Is an arched window on the 100th floor "connected to the ground"? – David Richerby Nov 28 '16 at 13:05
Well, more broadly, it's in a vertical plane and standing on something, even if not the earth itself. – Anton Sherwood Dec 06 '16 at 17:33

score 0 · Answer 3 · edited Apr 25 '18 at 11:53

I am a native French speaker, and a translator. I'd like to make a short terminology comparison. In English, for architecture, use arch, as in "pointed arch", in all cases. For geometry, use arc, or bow, like in bow-window.

In French, arc's first meaning is "bow" (cf. archer). Arche (Fr) is used to describe a large, primarily bow structure, typically in a bridge or a large space. But Arc (Fr) is just generic or for smaller construction elements. Pointed arch e.g. is said Arc Brisé (and not Arche). And for geometry as well it is Arc.

Exception: On Paris' Champs Élysees, you have the Arc de Triomphe, Rome has the Arc de Titus, which both are rather Arches (Fr) really by their dimensions, but for that kind of monument Arc is the traditionally used terminology. London has the Marble Arch.

And finally rainbow is said Arc-en-ciel (litt. a bow in the sky). How nice is that !

I hope this can somehow help & that no one will be upset this little linguistic invasion of mine.

You should probably add for context that the English words roots are from the French words Arche and Arc — Francisco Noriega, Mar 23 '23 at 06:34

Are "Arc" and "Arch" interchangeable?

3 Answers3