This is the 866th most frequent Armenian word.
քո
"Քո" means "your" in English.
In this sentence, 'քո' is used to specify that the mother being referred to is 'your' mother.
Ես տեսա քո մայրիկին։
I saw your mother.
The word 'քո' is again possessive, attributing the question to 'you'.
Քո հարցը շատ հետաքրքիր է։
Your question is very interesting.
The word 'քո' here indicates possession, showing that the house belongs to 'you'.