1) A storage container.
2) The modern equivalent of a siege engine.
2) Someone who is strong and/or physically imposing.
3) In roleplaying games, a melee damage-dealer (or to act as one).
1) There's a leak in the water tank.
2) My brother drives a tank in the army.
3) Is your sister still dating that tank of a football player?
4) LF tank for ZF run.