The relationship between and correct usage of the words Chronometry and Horology

If you want to know the true meaning of words, I suggest looking up the etymology, for this tells you the origin of the component parts of a word.

Whereas, the likes of Wikipedia often have various ‘in usage’ interpretations of meaning in context - which are often far from the original pure form and meaning.

Hence:

Horology - is made from: hora (hours, or time) logy - study. So horology is ‘the study of time’. The origin is latin.

‘The study and measurement of time’ and ‘The making of clocks and watches’ is horology.

Chronometry - khronos - time (Greek), and metry - the measurement of. From the Latin ‘metria’ and the Greek ‘metron’. So Chronometry is ‘the measurement of time’. Or ‘time measurement’. And a Chronometer is ‘the measurer of time’ ie a clock.

Online definitions of ‘chronometry’ say ‘the art of accurate time measurement’ or ‘the science of accurate time measurement’.

But I think this is ‘internet embelishment’ and that it really means what it says, simply: ‘the measurement of time’

Hopefully this gives you something more to go on, than what is really ‘hearsay’ from the words ‘in use’ - the pure origin of the meanings of words.

Perhaps the two similar words exist because they arise from Latin - and from Greek.

Note that an early chronometer (in Ancient Greece) might have been - a sun-dial. It really just means ‘measure-time’. A ‘time-measurer’.

However, marketing for posh watches often describes same as ‘chronometers’ presumably to elevate them into something more exclusive and expensive. This might be where your confusion about ‘what kinds of clocks does each term cover’ may come from. But I think that might be a ‘red herring’ - a distraction.

Although - ‘horologist’ does evoke to me, a craftsman with an eyepiece, making mechanical watches.

So... if you want ‘the study of time and time-keeping devices’ - use ‘horology’.

If you want ‘devices that measure time’ - use ‘chronometers’.

If you want ‘the art and science of making time measurement devices’ use ‘Chronometry’.

If you want ‘clocks and watches, whether mechanical or electronic’, what’s wrong with simply using ‘clocks and watches’?

Horology - etymology https://www.google.com.sg/search?q=etymology+of+horology&ie=UTF-8&oe=UTF-8&hl=en-sg&client=safari

Logy - etymology https://www.etymonline.com/word/-logy

Chronometer etymology https://www.merriam-webster.com/dictionary/chronometric