set
A dance or a group of dancers.
“Oh, dear, they need two more to complete the set.”
“My chess set is in the carriage. What do they need, rooks or pawns?”
“No, the set forming on the dance floor. There are three couples, they need a fourth. Hurry, go ask the Gillingham girl to dance.”
“But mother, I don’t want to dance. I want to go to the gaming room.”
“Absolutely not, Frankie. And don’t think I haven’t heard about your thirty pound loss at baccarat the other day.”
“Mother! We don’t talk about these things.”
“And if you go ask Cynthia Gillingham to dance, we won’t have to.”
Merriam-Webster
The basic formation in a country-dance or square dance
Wikipedia
Set dancing is based on quadrilles…Four couples are arranged in a square to dance, with each couple being in the middle of the sides of the square. Both the eight dancers in the group and the dance itself are called a ’set’. The dance is a sequence of several dance figures, which usually have a common theme or structure.
