The Collaborative International Dictionary of English v.0.48:

Social \So"cial\, a. [L. socialis, from socius a companion; akin
   to sequi to follow: cf. F. social. See Sue to follow.]
   1. Of or pertaining to society; relating to men living in
      society, or to the public as an aggregate body; as, social
      interest or concerns; social pleasure; social benefits;
      social happiness; social duties. "Social phenomena." --J.
      S. Mill.
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   2. Ready or disposed to mix in friendly converse;
      companionable; sociable; as, a social person.
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   3. Consisting in union or mutual intercourse.
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            Best with thyself accompanied, seek'st not
            Social communication.                 --Milton.
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   4. (Bot.) Naturally growing in groups or masses; -- said of
      many individual plants of the same species.
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   5. (Zool.)
      (a) Living in communities consisting of males, females,
          and neuters, as do ants and most bees.
      (b) Forming compound groups or colonies by budding from
          basal processes or stolons; as, the social ascidians.
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   Social science, the science of all that relates to the
      social condition, the relations and institutions which are
      involved in man's existence and his well-being as a member
      of an organized community; sociology. It concerns itself
      with questions of the public health, education, labor,
      punishment of crime, reformation of criminals, and the
      like.

   Social whale (Zool.), the blackfish.

   The social evil, prostitution.
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   Syn: Sociable; companionable; conversible; friendly;
        familiar; communicative; convival; festive.
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