Gisaeng is a fancy word for a special kind of woman in Korea a long, long time ago.
Gisaeng were trained to be really good at entertaining people. They learned how to dance, sing, play instruments, write pretty poems, and have interesting conversations. They were the life of the party!
But, Gisaeng were different from regular women. They were not allowed to marry and have babies. Instead, they lived in special houses with other Gisaeng and served high-class men who came to visit. They were like really fancy waitresses, but with more skills. Sometimes, they even had to do things that made them feel uncomfortable, but that wasn't right, so luckily it doesn't happen anymore.
So basically, Gisaeng were women who were trained to entertain others and serve a specific group of people in a special way.