This is the 5917th most frequent Russian word.
рот
Mouth.
'Рот' here directly refers to the anatomical part used for speaking and eating.
У него большой рот.
He has a big mouth.
'Рот' in this sentence emphasizes the action of using the mouth for speaking.
Она открыла рот, чтобы сказать что-то.
She opened her mouth to say something.
'Рот' is used to describe the physical state of the mouth during a facial expression.