Meaning of the word "on someone's watch" in English

What does "on someone's watch" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

on someone's watch

US /ɑn ˈsʌm.wʌnz wɑtʃ/
UK /ɒn ˈsʌm.wʌnz wɒtʃ/
"on someone's watch" picture

Idiom

during the period when someone is responsible for something

Example:
The company's profits declined significantly on his watch.
I won't let anything bad happen to this project on my watch.