Yes, stacks is a Scrabble word!

Verb

1. Load or cover with stacks

2. Arrange in stacks

3. Arrange the order of so as to increase one's winning chances

Noun

1. A large number or amount

2. Storage space in a library consisting of an extensive arrangement of bookshelves where most of the books are stored

3. An orderly pile

4. (often followed by `of') a large number or amount or extent

5. A list in which the next item to be removed is the item most recently stored (LIFO)

6. A large tall chimney through which combustion gases and smoke can be evacuated

7. A storage device that handles data so that the next item to be retrieved is the item most recently stored (LIFO)