billet-doux

Borrowed from French billet doux (literally “sweet note”).

• IPA^(key): /ˈbɪl.eɪ ˈdu/, /ˈbi.jeɪ ˈdu/

billet-doux (plural billets-doux)

1. A love letter.
   • 1847 January – 1848 July, William Makepeace Thackeray, chapter IV, in Vanity Fair […], London: Bradbury and Evans […], published 1848, →OCLC, page 31:

     "O heavenly, heavenly flowers!" exclaimed Miss Sharp, and smelt them delicately, and held them to her bosom, and cast up her eyes to the ceiling, in an ecstasy of admiration. Perhaps she just looked first into the bouquet, to see whether there was a billet-doux hidden among the flowers; but there was no letter.

   • 1873, [Edward Bulwer-Lytton], chapter VI, in Kenelm Chillingly: His Adventures and Opinions […], volume II, Edinburgh; London: William Blackwood and Sons, →OCLC, book IV, page 253:

     Adonis calls for a 'pick-me-up' before he has strength enough to answer a billet-doux from Venus.

• dulcet
• dolce far niente
• dolce vita