This is the 5936th most frequent Portuguese word.
boca
Mouth.
In this context, 'boca' is used to describe the opening of a container, showing the word's application beyond human anatomy.
O barco está com uma pequena abertura na boca da garrafa de vidro.
The bottle of glass has a small opening at its mouth.
In this sentence, 'boca' refers to the physical part of the body used for eating and speaking.
Ele estava com a boca cheia de comida.
He had his mouth full of food.
Here, 'boca' metaphorically signifies the expression of astonishment through opening the mouth.