Tank

A Tank is an armoured fighting vehicle designed for front-line combat which combines operational mobility and tactical offensive and defensive capabilities. It may refer to the following:
 * M808B Main Battle Tank - The UNSC Main Battle Tank.
 * M-145D Rhino - A prototype plasma-firing tank deployed by UNSC.
 * Wraith - The Covenant Main Battle Tank.
 * Type-52 Anti-Aircraft Artillery - Anti-Air variant from the Wraith.

Tank can also refer an enclosed heavily armed unit.
 * Flood tank form - A Flood Pure Form derived from a mutating Flood stalker form.

Tank could also refer to a container, usually for holding liquids, sometimes for compressed gases (gas tank).
 * Methane tank - A methane container used by the Unggoy to breathe in non-methane rich environments.
 * Methane recharge station - A portable methane container used by the Covenant.