pile (n.1) Look up pile at Dictionary.com
"mass, heap," early 15c., originally "pillar, pier of a bridge," from Middle French pile and directly from Latin pila "stone barrier, pillar, pier" (see pillar). Sense development in Latin from "pier, harbor wall of stones," to "something heaped up." In English, sense of "heap of things" is attested from mid-15c. (the verb in this sense is recorded from mid-14c.). The meaning "large building" (late 14c.) is probably the same word.
pile (n.2) Look up pile at Dictionary.com
"heavy pointed beam," from Old English pil "stake," also "arrow," from Latin pilum heavy javelin of the Roman foot soldier, literally "pestle" (source of Old Norse pila, Old High German pfil, German Pfeil "arrow"), of uncertain origin.
pile (n.3) Look up pile at Dictionary.com
"soft, raised surface upon cloth," mid-14c., "downy plumage," from Anglo-French pyle or Middle Dutch pijl, both from Latin pilus "a hair" (source of Italian pelo, Old French pel). Phonological evidence rules out transmission of the English word via Old French cognate peil, poil. Meaning "nap upon cloth" is from 1560s.
pile (v.) Look up pile at Dictionary.com
"to heap up," mid-14c.; see pile (n.1). Related: Piled; piling. Figurative verbal expression pile on "attack vigorously, attack en masse," is from 1894, American English.