Why are the parliamentarians called roundheads?

The term "Roundheads" refers to the supporters of the Parliament during the English Civil War (1642-1651), particularly those who opposed King Charles I. The name originated from the distinctive short haircuts worn by many of the Parliamentarians, in contrast to the longer hairstyles of the Royalists, who were often referred to as "Cavaliers." The Roundheads were primarily associated with Puritanism and sought to limit the power of the monarchy.