1. A vertical wood, metal, or concrete support or column for a building or other structure that is driven into the ground.
2. A long stake or pointed pole which is pushed into the ground to support something; such as, a building.
3. A collection or group of objects that are heaped, stacked, or laid on top of each other.
4. Etymology: "a pillar, a pier of a bridge", from Latin pila, "a stone barrier"; from Latin "pier, harbor wall of stones" then to "something that is heaped up".

To put something in a stack: "Mary piled the books high on the floor and her clothes were piling up on the chair."

"Sam, what do you plan to do with those newspapers after you pile them up?"

1. A rudimentary primary battery that consists of a series of disks made of two different metals; such as, zinc and copper, stacked alternately with electrolytes, soaked cloth , or paper disks.
2. The first source of a steady electric current, a simple form of electric battery developed by Alessandro Volta in 1799.

It consisted of alternating zinc and silver disks separated by material soaked in brine or salt water.