duenna

plural duennas

1. A chaperon of a young lady, usually an older woman.

   Then he placed her in a house and shut her up in a chamber, appointing ten old women as duennas to guard her, and forbade her to go forth to the Seven Palaces.

   1949, Joseph Campbell, The Hero with a Thousand Faces, Pantheon Books

   2 more examples

   'Madam, I have a secret to tell you.' Now the very word secret is enough to rouse any one's curiosity; and, giving a quick glance round to see if her duennas were on the alert, she prepared to listen, and I saw that her eye had caught sight of the letter.

   1834, L[etitia] E[lizabeth] L[andon], chapter XXIII, in Francesca Carrara. […], volume III, London: Richard Bentley, […], (successor to Henry Colburn), →OCLC, page 193

   I dared not do anything to spoil the image of me she had set up to adore. I had toadied to her when she was the awesome duenna of my darling, and a groveling something still persisted in my attitude toward her.

   1955 September 15, Vladimir Nabokov, Lolita, Paris: The Olympia Press […], →OCLC, page 85

2. A governess or nanny.