Meaning of the word "know what's what" in English

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

know what's what

US /noʊ wʌts wʌt/
UK /nəʊ wɒts wɒt/
"know what's what" picture

Idiom

to have a good understanding of a situation or of how things work

Example:
She's been in this business for years, so she really knows what's what.
You need to spend some time learning the ropes if you want to know what's what around here.