What is Seersucker?
It's a woven cotton fabric with a puckered sewing pattern and texture. It is woven in a way that some threads bunch together, which gives it a crinkled look in some places. Because of its structure, it is iron-free, airy and breathable, and therefore typically used for spring or summer temperatures.
A little bit of history: this fabric came originally from India to England, and in the 1600s via the East India Company to the US. The name comes from the Persian words for "milk and sugar," ("shirushakar"), which refers to the different types of weaving. It was over time being pronounced as Seersucker.