Meaning of “clockwork” - Learner’s Dictionary

clockwork

noun uk us /ˈklɒkwɜːk/

[ U ] a system of machinery that starts when you turn a handle or key:

a clockwork toy
(as) regular as clockwork

extremely regularly:

The bell rang at 8 a.m., regular as clockwork.
run/go like clockwork

to happen exactly as planned, with no problems:

The whole event went like clockwork

(Definition of “clockwork” from the Cambridge Learner’s Dictionary © Cambridge University Press)