Yes, gain is a Scrabble word!

Verb

1. Obtain

2. Win something through one's efforts

3. Derive a benefit from

4. Reach a destination, either real or abstract

5. Obtain advantages, such as points, etc.

6. Rise in rate or price

7. Increase or develop

8. Earn on some commercial or business transaction; earn as salary or wages

9. Increase (one's body weight)

Noun

1. A quantity that is added

2. The advantageous quality of being beneficial

3. The amount of increase in signal power or voltage or current expressed as the ratio of output to input

4. The amount by which the revenue of a business exceeds its cost of operating