Yes, tree is a Scrabble word!

Verb

1. Force a person or an animal into a position from which he cannot escape

2. Plant with trees

3. Chase an animal up a tree

4. Stretch (a shoe) on a shoetree

Noun

1. A tall perennial woody plant having a main trunk and branches forming a distinct elevated crown; includes both gymnosperms and angiosperms

2. A figure that branches from a single root

3. English actor and theatrical producer noted for his lavish productions of Shakespeare (1853-1917)