The Collaborative International Dictionary of English v.0.48:

Hematoma \Hem`a*to"ma\ (h[=e]`m[.a]*t[=o]"m[.a] or
   h[e^]m`[.a]*t[=o]"m[.a]), n. [NL. See Hema-, and -oma.]
   (Med.)
   A localised leakage of blood from the blood vessels into
   nearby tissues, usually confined within a tissue or organ;
   especially, a local swelling produced by an effusion of blood
   beneath the skin, which may clot and discolor the affected
   area.
   [1913 Webster]

WordNet (r) 3.0 (2006):

hematoma
    n 1: a localized swelling filled with blood [syn: hematoma,
         haematoma]