sock hop

English Wikipedia has an article on:

sock hop

Wikipedia

• sockhop, sock-hop

Because dancers were required to remove their shoes to protect the varnished floor of the gymnasium.

sock hop (plural sock hops)

1. (US, historical) 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.
   • 1973 October, Joseph Kanon, “On the Strip”, in The Atlantic‎^[1]:

     But unlike any other nostalgia film, American Graffiti has been able to supply the details and step quickly beyond them—after the opening scenes, they're just assumed pieces of background. The words are there […] and the staging of a sock hop in the gym is virtually flawless, but they are part of a total experience, not the experience itself.

   • 2005 June 13, Edmund White, “My Women”, in New Yorker‎^[2]:

     I had no idea then how boys wooed girls. I guessed it was a matter of joshing and shared nothings and hours of scuffing through autumn leaves and even more hours of clenches during the slow numbers at the sock hop.

   • 2012 October 24, Jon Caramanica, “No More Kid Stuff for Taylor Swift”, in The New York Times‎^[3], →ISSN:

     “I Knew You Were Trouble,” one of the year’s great pop songs, begins like a sock-hop anthem, with jaunty guitars.