French safe

From French +‎ safe. Compare earlier French letter. Attested from the mid 19th century.

French safe (plural French safes)

1. (colloquial, euphemistic) A condom.
   • 1877, “What a Latin prescription did”, in Cincinnati Lancet & Observer‎^[1], volume 20, page 713:

     The druggist examined the ets and the cuis in it, and felt sure he knew just what the doctor wanted — proceeded to fill the order, and a French safe was nicely folded up and put in a suitable box labelled “use as directed” and handed to the young lady

   • 1982, David Helwig, The Rain Falls Like Rain, page 183:

     Ashes, ashes. A used French safe / is blown across the city sidewalk.

   • 2002, Wes Pipe, Memories of Mines‎^[2], page 1:

     We had this daily tournament, to see who could snag, the most French safes with his stick. A French safe is a condom, don’t ask me where the name comes from.

• “French, adj. and n.”, in OED Online  ⁠, Oxford, Oxfordshire: Oxford University Press, September 2009.