IPA: /ˈklɒk.wɜːk/
KK: /ˈklɑkˌwɜrk/
A system of gears and springs that makes a clock or similar device work, often used to describe the inner workings of something or the precision of its operation.
The old toy was powered by a simple clockwork mechanism that made it move.
Clockwork → The word is formed from "clock" (from Old French *cloche*, meaning bell) and "work" (from Old English *weorc*, meaning activity or labor). The term "clockwork" refers to the mechanism of a clock that operates through a series of coordinated movements, akin to a well-organized activity or labor.
Think of a 'bell' ('clock') that operates through a series of 'activities' ('work') — that's why clockwork refers to the precise mechanism of a clock.