duenna

noun

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

   “'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.”

   “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.”

   “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.”

2. A governess or nanny.