French letter

From French +‎ letter. Compare earlier French pox, French-sick (“syphilis”), or later French safe, French tickler (“condom”), or French kiss. Attested from the 19th century.

French letter (plural French letters)

1. (UK, Ireland, Australia, New Zealand, dated, euphemistic) A condom.

   Synonyms: see Thesaurus:condom

   • 1984, Leslie Thomas, In my Wildest Dreams, page 289:

     ‘So you’re fifteen – and you know the function of a “French letter”? You are familiar with its use?’
     ‘I know what it’s for, sir, yes.’

   • 2012, Courtney Milan, A Kiss for Midwinter‎, page 80:

     “I suppose it’s too much to hope that you have a question about gonorrhea. Those questions are so much easier to answer.” […]
     “I was going to ask about what you said earlier. That you’d... that you’d... not used a French letter in eighteen months.”

• Frenchie

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