KGYSAK: 가방 vs 봉투

The only reason why I bring this up is that in English we use the same word "bag" for a purse, satchel, and indeed a plastic bag used at a grocery store. In Korean, the plastic bag that polite store clerks ask if you need to go with your purchased goods ("봉투 필요하세요?") I used to make the mistake of telling the clerk 가방 필요 없어요. I'm sure she was wondering why I was telling her that I had no need for a man purse.

This native Korean word means "bag" as in:
서류 가방 document bag
가죽 가방 leather bag
여행 가방 travel bag [just like 짐 (朕)]

봉투 (封套)
bag, sack, envelope

In summary, a 가방 is a fashionable, purchasable briefcase or purse that is worn around the shoulders. A 봉투 is a thin, plastic non-eco friendly shopping bag accompanied by loaves of bread and groceries. 봉투 can also be a mailing envelope. If you ask for a 봉투 and someone happily offers you a thin black plastic bag used to carry fruit, politely smile and ask instead for a 편지 봉투 instead.