pile 2 
(pīl)
(pīl)n.
1. A heavy post of timber, concrete, or steel, driven into the earth as a foundation or support for a structure.
2. Heraldry A wedge-shaped charge pointing downward.
3. A Roman javelin.
tr.v. piled, pil·ing, piles
1. To drive piles into.
2. To support with piles.
[Middle English, from Old English pīl, shaft, stake, from Latin pīlum, spear, pestle.]
pile2