clockwork

/ˈklɒkwɜːk/

IPA: /K L AA1 K W ER0 K/

noun
  1. 1

    A mechanism powered by a coiled spring and regulated by some form of escapement; the power is transmitted through toothed gearwheels and used to drive a mechanical clock, toy, or other device.

Source: https://en.wiktionary.org/wiki/clockwork