The Collaborative International Dictionary of English v.0.48:

Piles \Piles\, n. pl. [L. pila a ball. Cf. Pill a medicine.]
   (Med.)
   The small, troublesome tumors or swellings about the anus and
   lower part of the rectum which are technically called
   hemorrhoids. See Hemorrhoids.

   Note: [The singular pile is sometimes used.]
         [1913 Webster]

   Blind piles, hemorrhoids which do not bleed.
      [1913 Webster]

WordNet (r) 3.0 (2006):

piles
    n 1: pain caused by venous swelling at or inside the anal
         sphincter [syn: hemorrhoid, haemorrhoid, piles]
    2: a large number or amount; "made lots of new friends"; "she
       amassed stacks of newspapers" [syn: tons, dozens,
       heaps, lots, piles, scores, stacks, loads,
       rafts, slews, wads, oodles, gobs, scads,
       lashings]