Lewis & Short

2. pīlă, ae, f. [for pigla, from root pag-, pig-, of pango, pe-pig-i, q. v.],

  1. I. a pillar (syn. columna): pila, quae parietem sustentat, ab opponendo dicta est, Paul. ex Fest. p. 204 Müll.: locavit pilas pontis in Tiberim, Liv. 40, 51: salax taberna a pileatis nona fratribus pila, of the temple of Castor and Pollux, Cat. 37, 1: nulla taberna meos habeat neque pila libellos, i. e. they are not to be publicly sold (as the booksellers had their stalls around the pillars of public buildings), Hor. S. 1, 4, 71; Vitr. 6, 11: pilas operibus subdere, Sen. Q. N. 6, 302; Plin. 11, 10, 10, § 23; Mart. 7, 61, 5.
  2. II. Transf., a pier or mole of stone: saxea, Verg. A. 9, 711; Vitr. 5, 12; Suet. Claud. 20; Sil. 4, 297.