Monkey's puzzle

Mon´key's puz´zle

1.

(Bot.) A lofty coniferous Chilian tree (Araucaria araucana, formerly Araucaria imbricata), the branches of which are so crowded and intertwisted "as to puzzle a monkey to climb." It is also called monkey puzzle and monkey puzzle tree. The edible nuts are over an inch long, and are called piñon by the Chilians.

Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.