The Collaborative International Dictionary of English v.0.48:

Vomit \Vom"it\, n. [L. vomitus, from vomere, vomitum, to vomit;
   akin to Gr. ?, Skr. vam, Lith. vemiti. Cf. Emetic,
   Vomito.]
   [1913 Webster]
   1. Matter that is vomited; esp., matter ejected from the
      stomach through the mouth.
      [1913 Webster]

            Like vomit from his yawning entrails poured.
                                                  --Sandys.
      [1913 Webster]

   2. (Med.) That which excites vomiting; an emetic.
      [1913 Webster]

            He gives your Hollander a vomit.      --Shak.
      [1913 Webster]

   Black vomit. (Med.) See in the Vocabulary.

   Vomit nut, nux vomica.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Black vomit \Black" vom"it\ (Med.)
   A copious vomiting of dark-colored matter; or the substance
   so discharged; -- one of the most fatal symptoms in yellow
   fever.
   [1913 Webster] Black wash

WordNet (r) 3.0 (2006):

black vomit
    n 1: caused by a flavivirus transmitted by a mosquito [syn:
         yellow jack, yellow fever, black vomit]