Yes, tank is a Scrabble word!
...and is worth 8 points in Scrabble, and 9 points in Words with Friends
tank
Verb
1. Store in a tank by causing (something) to flow into it
2. Consume excessive amounts of alcohol
3. Treat in a tank
Noun
1. An enclosed armored military vehicle; has a cannon and moves on caterpillar treads
2. A large (usually metallic) vessel for holding gases or liquids
3. As much as a tank will hold
4. A freight car that transports liquids or gases in bulk
5. A cell for violent prisoners
What Scrabble words can I make with the letters in tank?
3 Letter Words
2 Letter Words