The Collaborative International Dictionary of English v.0.48:

Porta \Por"ta\, n.; pl. Port[ae]. [L., a gate. See Port a
   hole.] (Anat.)
   (a) The part of the liver or other organ where its vessels
       and nerves enter; the hilus.
   (b) The foramen of Monro. --B. G. Wilder.
       [1913 Webster]

WordNet (r) 3.0 (2006):

porta
    n 1: an aperture or hole that opens into a bodily cavity; "the
         orifice into the aorta from the lower left chamber of the
         heart" [syn: orifice, opening, porta]