Yes, horses is a Scrabble word!

Verb

1. Provide with a horse or horses

Noun

1. Solid-hoofed herbivorous quadruped domesticated since prehistoric times

2. A padded gymnastic apparatus on legs

3. Troops trained to fight on horseback

4. A framework for holding wood that is being sawed

5. A chessman shaped to resemble the head of a horse; can move two squares horizontally and one vertically (or vice versa)