IPA: //dʊˈɛnə//
KK: /dwen-uh/
An older woman who looks after and guides a young lady, often serving as a chaperon or governess.
In the story, the young girl was always accompanied by her duenna, who ensured she behaved properly in society.
Duenna originates from the Spanish word 'dueña', meaning a lady or mistress, which itself comes from the Latin 'domina' (meaning lady or mistress).
Think of a 'lady' ('domina') who is in charge or a 'mistress' ('dueña') — that's why a duenna is a woman who acts as a guardian or chaperone.