お〜・ご〜 (prefix): honorific prefix

Adds respect or politeness to nouns, and to objects of the listener.

お is added to native Japanese words (お名前, お金); ご to Chinese-origin words (ご家族, ご住所). It can show respect for someone's things, or just politeness: お茶, ご飯. Never put it on your own things when speaking to others.