"patter consisting of dots of uniform size and arrangement," especially on fabric, 1851 (polka-spot and polka-dotted are used in 1849), when they were in fashion, from polka (n.) + dot (n.). Named for the dance, for no reason except its popularity, which led to many contemporary products and fashions taking the name (polka hat, polka-jacket, etc.). They had a revival in fashion c. 1873. Related: Polka-dots.