Wiktionary
n. In the 1950s, informal sponsored dance at American high schools, typically held on the grounds of the high school itself in the gymnasium or cafeteria.
Wikipedia
A sock hop or sox hop, often also called a record hop or just a hop, was an informal sponsored dance event for teenagers in mid-20th-century North America, featuring popular music.
Usage examples of "sock hop".
It's great to go to-we're league champions in basketball and our square-dance team is state runner-up and we have a swell sock hop every Wednesday.
They danced to it all the same, like the band was singing about a sock hop.
Why not just have a sock hop and be done with W): George Chizmar, Ewen's most artistic student, had done a small chalk sketch of gondolas on a canal at sunset and a gondolier in a huge straw fedora leaning against the tiller as a gorgeous panoply of pinks and reds and oranges stained both sky and water.
It was sort of like the way it was when you were a kid and your parents wanted to know about Susie at the freshman sock hop.
She thought he'd be proud of her, and she knew she could show him how he could sell, too- it was only a matter of studying the editor's prejudices -but a week after that Fred took another girl to the sock hop.