This is the 3rd most frequent Vietnamese word.
có
"có" means "to have" or "there is/are."
Here, 'có' indicates possession, meaning 'to have'.
Tôi có một con mèo.
I have a cat.
Here, 'có' is part of the question structure meaning 'do'.
Bạn có thấy cái bút không?
Do you see the pen?
Here, 'có' intensifies the adjective, similar to 'seems' or 'is'.