summerhouse        
noun [ C ] uk/ˈsʌm.ə.haʊs/ us/ˈsʌm.ɚ.haʊs/
 (花园中的)凉亭,凉棚
a small building in a garden used for sitting in during the summer
  US(海滨或山中的)避暑别墅 
a house at the beach or in the mountains that you live in for part or all of the summer