The Collaborative International Dictionary of English v.0.48:

Pillory \Pil"lo*ry\, n.; pl. Pillories. [F. pilori; cf. Pr.
   espitlori, LL. piloricum, pilloricum, pellericum, pellorium,
   pilorium, spilorium; perhaps from a derivative of L.
   speculari to look around, observe. Cf. Speculate.]
   A frame of adjustable boards erected on a post, and having
   holes through which the head and hands of an offender were
   thrust so as to be exposed in front of it. --Shak.
   [1913 Webster]