성인 means adult. You’ll see this word at places such as the movie theater, where there is a different price for adults or kids (the word for kid is 어린). You’ll also see this word at businesses designated for adults, where kids for whatever reason are not allowed. Once you know the word 성인, you will realize there are businesses aimed at adults in various neighborhoods across Korea.
This BC Bang also appears to be aimed at adults. This photo was taken near Daegu’s KTX station.
This corner store’s name is 성인상회. I’m not really familiar with the word 상회, but according to the dictionary it means store.
This store is a 성인용품 store. 용품 means “goods” or “article”. The Chinese character for 용 means use, while the character for 품 means goods.
This is a sidewalk sign for a 성인용품 store. 부부 means married couple. This photo was taken near Dongdaemun.
This poster advertises ESL English classes for adults. 영어반 means English class. This photo was taken in L.A.’s Koreatown where Korean adult immigrants need to learn English.
영화 means movie. This is a movie theater for adults. As I recall, this photo was taken in Yongsan, an area of Seoul.
This sign found outside a PC Bang says 미성년자 (as in people who are not yet adults) are not allowed (금지) after (이후) 10 PM.