The Collaborative International Dictionary of English v.0.48:

Trental \Tren"tal\, n. [LL. trentale, fr. L. triginta thirty;
   akin to tres three: cf. OF. trentel. See Three, and cf.
   Trigintal.]
   1. (R. C. Ch.) An office and mass for the dead on the
      thirtieth day after death or burial. "Their trentals and
      their shrifts." --Spenser.
      [1913 Webster]

   2. Hence, a dirge; an elegy.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Trental
    n 1: a drug (trade name Trental) used to treat claudication;
         believed to increase the flexibility of red blood cells so
         they can flow through the blood vessels to the legs and
         feet [syn: pentoxifylline, Trental]