The Collaborative International Dictionary of English v.0.48:

Algometer \Al*gom"e*ter\, n. [Gr. ? pain + -meter.] (Psychol.)
   An instrument for measuring sensations of pain due to
   pressure. It has a piston rod with a blunted tip which is
   pressed against the skin. -- Al*gom"e*try, n. --
   Al`go*met"ric, *met"ric*al, a. -- Al`go*met"ric*al*ly,
   adv.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

algometer
    n 1: device for measuring pain caused by pressure