Seersucker

This is a light (traditionally) cotton fabric that has a crinkled appearance. It’s known as a good fabric for hot weather, since the texture tends to hold the fabric off the wearer’s skin.

It’s often associated with narrow pinstripes. Some people might use the word to refer to the fabric pattern, rather than what it’s actually made of.

Why I Looked It Up

From Tomorrow, and Tomorrow, and Tomorrow:

At the arcade, a man in a seersucker suit suggested she try the caves…