The Collaborative International Dictionary of English v.0.48:

Citation \Ci*ta"tion\, n. [F. citation, LL. citatio, fr.L.
   citare to cite. See Cite]
   1. An official summons or notice given to a person to appear;
      the paper containing such summons or notice.
      [1913 Webster]

   2. The act of citing a passage from a book, or from another
      person, in his own words; also, the passage or words
      quoted; quotation.
      [1913 Webster]

            This horse load of citations and fathers. --Milton.
      [1913 Webster]

   3. Enumeration; mention; as, a citation of facts.
      [1913 Webster]

   4. (Law) A reference to decided cases, or books of authority,
      to prove a point in law.
      [1913 Webster]

WordNet (r) 3.0 (2006):

citation
    n 1: an official award (as for bravery or service) usually given
         as formal public statement [syn: citation,
         commendation]
    2: (law) the act of citing (as of spoken words or written
       passages or legal precedents etc.)
    3: a short note recognizing a source of information or of a
       quoted passage; "the student's essay failed to list several
       important citations"; "the acknowledgments are usually
       printed at the front of a book"; "the article includes
       mention of similar clinical cases" [syn: citation, cite,
       acknowledgment, credit, reference, mention,
       quotation]
    4: a passage or expression that is quoted or cited [syn:
       quotation, quote, citation]
    5: a summons that commands the appearance of a party at a
       proceeding
    6: thoroughbred that won the triple crown in 1948

Moby Thesaurus II by Grady Ward, 1.0:

47 Moby Thesaurus words for "citation":
   accolade, acknowledgment, assault, attack, award, by-line, case,
   censure, certiorari, confession, credit line, cross reference,
   demonstration, eulogy, example, exemplification, garnishment,
   guerdon, habeas corpus, honorable mention, illustration,
   implication, impugnment, incrimination, inculpation, instance,
   involvement, item, kudos, mention, monition, panegyric, particular,
   praise, quotation, reference, reward, salutation, signature,
   subpoena, summons, trademark, tribute, venire, venire de novo,
   venire facias, writ of summons



Bouvier's Law Dictionary, Revised 6th Ed (1856):

CITATION, practice. A writ issued out of a court of competent, jurisdiction,
commanding a person therein named to appear and do something therein
mentioned, or to show cause why he should not, on a day named. Proct. Pr.
h.t. In the ecclesiastical law, the citation is the beginning and foundation
of the whole cause; it is said to have six requisites, namely.: the
insertion of the name of the judge; of the promovert; of the impugnant; of
the cause of suit; of the place; and of the time of appearance; to which may
be added the affixing the seal of the court, and the name of the register or
his deputy. 1 Bro. Civ. Law, 453-4; Ayl. Parer. xliii. 175; Hall's Adm. Pr.
5; Merl. Rep. h.t. By, citation is also understood the act by which a
person is summoned, or cited.