The open window is an important symbol of freedom and opportunity in Kate Chopin's "The Story of an Hour." When Mrs. Mallard first hears of her husband's death, she sits alone in her room in front of the open window overlooking the street. She takes note of the sounds and sights outside of that window. She hears birds singing and a peddler calling; she sees the blue color of the sky and the puffy clouds. And then she has an epiphany. The window is the means by which Mrs. Mallard's epiphany comes about.
We learn that Mrs. Mallard has felt quite stifled in her marriage. She says that, although her husband was not a bad person, he was controlling. But now she can act as she wants, think what she wants, and be who she wants to be:
There would be no powerful will bending hers in that blind persistence with which men and women believe they have a right to impose a private will upon a fellow-creature.
All Mrs. Mallard can think of is her freedom. She does love Mr. Mallard and is upset over his death, but she realizes she now has a chance to live. As a married woman, she had never been able to make her own decisions. Although she was not literally a prisoner, Mrs. Mallard's will was suppressed, and she was compelled to give in to her husband's will. Now, as a widow, Mrs. Mallard will have the freedom, sanctioned by society, to make her own choices without worrying about what others think.
Chopin uses the open window as a symbol of opportunity. Mrs. Mallard's life is about to change, and she thinks she will have many opportunities for happiness.