treehouse
noun/ˈtɹiːˌhaʊs/
Etymology From tree + house. First use appears c. 1867. See cite below.
1
US A house, or similar structure within a tree, or several trees, built with light materials.
- so that I am high and dry, and have all the better view too, quite a grand flight of steps-a broad ladder-up into my house. The Mahaga lads and I call it my tree-house.1867, Charlotte Mary Yonge, Life of John Coleridge Patteson, Missionary Bishop of the Melanesian Islands, Volume 2, page 177:
2
A tropical residence built in a tree, or on stilts.