This is the 905th most frequent Vietnamese word.
cá
"Fish."
In this usage, 'cá' refers to 'fish' as an animal or food.
Tôi thích ăn cá mỗi ngày.
I like eating fish every day.
Here, 'cá' is part of the idiom 'trong cá ló' meaning being among those who are outstanding.
Anh ấy là một người trong cá ló.
He is among the exceptional ones.
In this sentence, 'cá' is used to describe actual fish living in water.