Translation:Aunt and uncle
친삼촌 - unmarried younger brother of one's father. If married, 작은아버지
외삼촌 - mother's younger brother regardless of marital status
In my opinion
삼촌 (uncle/young man) is an endearing, familiar 아저씨 (mister).
이모 (auntie/young lady) is a more flattering, familiar 아주머니 (ma'am).