clock‧work /ˈklɒk-wɜːk $ ˈklɑːk-wɜːrk/ noun [uncountable]

1. British English clockwork toys, trains, soldiers etc have machinery inside them that makes them move when you turn a key:
mechanical toys powered by clockwork
The tape was driven by a clockwork motor.

2. go/run like clockwork to happen in exactly the way you had planned:
The concert went like clockwork.

3. like clockwork (also (as) regular as clockwork) happening at the same time and in the same way every time:
Matt came round each Friday, regular as clockwork.

4. with clockwork precision/accuracy in an extremely exact way

[TahlilGaran] Dictionary of Contemporary English ▲