A parasol is a thin umbrella used for the sun instead of for rain. Brolly in england parasol is rare, but understood sunshade is anything that blocks the sun的同义词 A parasol is not a frequently used term in the us anymore but it is a hand-held umbrella that is only meant to be used as sun protection.
Some may argue that the large beach umbrellas are parasols. 梧桐更兼细雨,到黄昏、点点滴滴。 on parasol-trees a fine rain drizzles as twilight grizzles.