The Collaborative International Dictionary of English v.0.48:

Hilum \Hi"lum\, n. [L., a little thing, trifle.]
   1. (Bot.) The eye of a bean or other seed; the mark or scar
      at the point of attachment of an ovule or seed to its base
      or support; -- called also hile.
      [1913 Webster]

   2. (Anat.) The part of a gland, or similar organ, where the
      blood vessels and nerves enter; the hilus; as, the hilum
      of the kidney.
      [1913 Webster]

WordNet (r) 3.0 (2006):

hilum
    n 1: (anatomy) a depression or fissure where vessels or nerves
         or ducts enter a bodily organ; "the hilus of the kidney"
         [syn: hilus, hilum]
    2: the scar on certain seeds marking its point of attachment to
       the funicle