The Collaborative International Dictionary of English v.0.48:

Sex \Sex\, n. [L. sexus: cf. F. sexe.]
   1. The distinguishing peculiarity of male or female in both
      animals and plants; the physical difference between male
      and female; the assemblage of properties or qualities by
      which male is distinguished from female.
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   2. One of the two divisions of organic beings formed on the
      distinction of male and female.
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   3. (Bot.)
      (a) The capability in plants of fertilizing or of being
          fertilized; as, staminate and pistillate flowers are
          of opposite sexes.
      (b) One of the groups founded on this distinction.
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   The sex, the female sex; women, in general.
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