An Etymological Dictionary of Astronomy and Astrophysics

An assemblage of things laid or lying one upon the other (Dictionary.com).

Etymology (EN): M.E., from M.Fr. pile and directly from L. pila “pillar, mole of stone.”

Etymology (PE): Tal “heap; hill,” maybe related to Gk. tylos “a hard and thickened area on the skin, callus, lump,” tymbos “burial mound, grave, tomb;” Av. tuma- “fat;” L. tumere “to swell,” tumulus “raised heap of earth,” tumidus “swollen;” tumor “a swelling.”