(verb)
to take in or let out a long, deep breath, usually audibly, as an expression of relief, sadness, or tiredness;
e.g. I heard him sigh when he saw all of the letters he still had to read.
(verb)
to make a whispering or swishing sound similar to that of someone breathing audibly, usually describing the wind;
e.g. They sat without talking, listening to the wind sigh in their ears.
(noun)
a long, deep breath taken in or let out, usually audibly, as an expression of relief, sadness, or tiredness;
e.g. She gave out a long sigh as she turned and walked back the way she had come.
(noun)
a whispering or swishing sound similar to the sound of someone breathing audibly, especially one made by moving air;
e.g. We heard a sigh as we finally got the sealed lid off the container.