Meaning of the word "all of a sudden" in English

What does "all of a sudden" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

all of a sudden

US /ɔːl əv ə ˈsʌdən/
UK /ɔːl əv ə ˈsʌdən/

Idiom

suddenly and unexpectedly

Example:
All of a sudden, the lights went out.
He appeared all of a sudden from behind the bushes.