The Collaborative International Dictionary of English v.0.48:

Semen \Se"men\ (s[=e]"m[e^]n), n.; pl. Semina
   (s[e^]m"[i^]*n[.a]). [L., from the root of serere, satum, to
   sow. See Sow to scatter seed.]
   1. (Bot.) The seed of plants.
      [1913 Webster]

   2. (Physiol.) The seed or fecundating fluid of male animals;
      sperm. It is a white or whitish viscid fluid secreted by
      the testes, characterized by the presence of spermatozoids
      to which it owes its generative power.
      [1913 Webster]

   Semen contra, or Semen cinae or Semen cynae, a strong
      aromatic, bitter drug, imported from Aleppo and Barbary,
      said to consist of the leaves, peduncles, and unexpanded
      flowers of various species of Artemisia; wormseed.
      [1913 Webster]