Word for the thing that moves back and forth in a watch mechanism

Question

The reason I'm asking is because it is a singular word in Swedish "oro". It is a fitting technical term that translates roughly to "concern, fidgeting".

I find it curious English not having a singular word for this.

I have found "balance wheel", "watch movement" I suppose watch is redundant in context. I've also seen "watch calibre", same caveat.

Is calibre the word I'm looking for?

As a reaction to the helpful answer by Ricky. I'd like to find a word that is not as ambiguous or context dependent. I don't mind an exotic word.

Answer 1

I believe that would be the escapement.

Here’s a description:

The escapement is a mechanism that translates rotational energy into lateral impulses. The tick-tock sound you hear when holding a watch to your ear is from the escapement. The pallet fork locks and unlocks with the escape wheel at each vibration of the balance wheel.
_{Source: Hodinkee — Watch 101}

In real life, though, few people would have any idea of what you’re talking about.

I submit to you instead a mashup that employs a few productive English language tactics:

• onomatopoeia (the process of creating a word that phonetically imitates, resembles, or suggests the sound that it describes)

• metonomy (a figure of speech in which a thing or concept is referred to by the name of something closely associated with that thing or concept)

• derivational suffixing with -er (turning a verb into noun that is person or thing that does the verb).

So, here you go . . .

tick-tocker

Here’s an example usage:

I can’t hear anything; the tick-tocker must be broken.

Proceed at your own risk.

Answer 2

Just balance will do.

balance

15. Also called balance wheel. Horology. a wheel that oscillates against the tension of a hairspring to regulate the beats of a watch or clock.

https://www.dictionary.com/browse/balance

Answer 3

The escapement, as defined by Merriam Webster is:

a device in a timepiece which controls the motion of the train of wheelwork and through which the energy of the power source is delivered to the pendulum or balance by means of impulses that permit a tooth to escape from a pallet at regular intervals

See also How a Mechanical Watch Works on YouTube

Answer 4

While that part is called oro in Swedish, it's onrust in Dutch and unruh in German. A naïve translation for both would be unrest, but not in the sense of civil unrest, but rather uncalm and indeed fidgeting.

Going by Wikipedia, the correct English name of that part is indeed balance wheel, which doesn't have those same connotations. Note that the name for this part seems to be similar in French, Italian, and Polish.

Answer 5

I find it curious English not having a singular word for this.

We have a few. It depends on precisely what you wish to describe.

The pure back-and-forth movement, especially whithin limits:

Oscillate

OED:
verb [ no obj. ]
move or swing back and forth in a regular rhythm: the grain pan near the front of the combine oscillates back and forth.
• [ with adverbial ] vary or fluctuate between two states, limits, opinions, etc.: he was oscillating between fear and bravery.

Whereas oscillate pertains to the back-and-forth movement of the thing, escapement pertains to the delivery of power (the power of the spring escapes into the cogs that move the hands).

I'd like to find a word that is not as ambiguous

Yes, that is to be avoided.

or context dependent

No. All Indo-European languages (including Swedish) are context-dependent, it is a principle, you can't get away from it. The sense of the word is modulated by the context that it is used in. Refer to the examples in the OED definition:

• the balance wheel oscillates between clockwise and anti-clockwise,
• the claw oscillates between capture and escape,
• the person oscillated between fear and bravery.