There are two interesting aspects to the title of this incredible novel that can both be related to one of the key themes, which is that of gender and how Allende presents us with a world that is dominated by men. Let us consider the first element. Firstly, Eliza, the protagonist of the story, is a "daughter." This immediately stresses her position as a dependent and as an inferior woman in a man's world, as she is not only defined by her relationship to her father, but her gender is also emphasised. Secondly, she is a daughter "of fortune," which of course has two meanings. Firstly, she is due to inherit wealth from her parents, which again reinforces her subordinate position as a rich prize to any man out there, and secondly, she is fortunate, or lucky, in the way that her life turns out.
You might like to consider the way in which the theme of patriarchy is related to the title through the action of the novel. Let us remember that later on in the story, Eliza, as part of her rebellion against the forces of patriarchy, becomes a man by dressing herself in men's clothing. However, it is only when she wears female clothing again that she is able to be at peace with her identity as a woman and gain a measure of self-respect and confidence. She is therefore wealthy, metaphorically speaking, when she is able to accept her gendered identity.