Yes, rung is a Scrabble word!

Verb

1. Sound loudly and sonorously

2. Ring or echo with sound

3. Make (bells) ring, often for the purposes of musical edification

4. Get or try to get into communication (with someone) by telephone

5. Extend on all sides of simultaneously; encircle

6. Attach a ring to the foot of, in order to identify

Noun

1. A crosspiece between the legs of a chair

2. One of the crosspieces that form the steps of a ladder