treehouse

noun2

1. •
   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
2. •
   A tropical residence built in a tree, or on stilts.