A metaphor is a direct comparison, when you compare something to something else by saying it IS that something. For example, Eva is not literally inside her cat. It’s a metaphor.
Specific metaphors are figures of speech used in a story to bring in deeper meaning. Here’s another example from the beginning of the story.
She still remembered the weight of the privilege she had borne over her body during adolescence, which she had dropped now--who knows where?
Using the words “weight of the privilege” makes this a metaphor. She is not carrying around an actual privilege, because privilege is an idea.
She had to drop that useless attribute of her personality somewhere; as she turned a corner, somewhere in the outskirts. Or leave it behind on the coatrack of a second-rate restaurant like some old useless coat.
Here’s another example, because you can’t actually leave your attitude on a coatrack.
Metaphors like this make the story more meaningful because the reader is caught by the images and takes time to think about the comparison. They are make the story more poetic.