Supply depot

"In order to equip additional personnel you must have enough supply depots to support them."

- Terran Adjutant

The Supply Depot houses all the goods, tools and accessories that are necessary for the running of a Terran base. It is used by both military units and colonists. Such storage includes weapons, ammunition and even SCVs.

Supply Depots in StarCraft I
The Supply Depot is is by far one of the most important buildings in the Terran tech tree. Similarly to the Pylon (Protoss) or the Overlord (Zerg), it provides "supply points" which allow for the construction of new units. Unlike Overlords and Pylons, however, it does not have any additional abilities.

Abilities
In StarCraft II, Supply Depots are able to sink into the ground, enabling friendly troops to pass over them; this does not render them immune to enemy fire, however. They are also a more compact cube-like shape, enabling them to more efficiently block movement of enemy troops. They are currently being updated to prevent even small units from passing between groups of them. The ability takes 2 seconds.
 * Lower/Raise