The Collaborative International Dictionary of English v.0.48:

Summons \Sum"mons\, n.; pl. Summonses. [OE. somouns, OF.
   sumunse, semonse, semonce, F. semonce, semondre to summon,
   OF. p. p. semons. See Summon, v.]
   1. The act of summoning; a call by authority, or by the
      command of a superior, to appear at a place named, or to
      attend to some duty.
      [1913 Webster]

            Special summonses by the king.        --Hallam.
      [1913 Webster]

            This summons . . . unfit either to dispute or
            disobey.                              --Bp. Fell.
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            He sent to summon the seditious, and to offer
            pardon; but neither summons nor pardon was regarded.
                                                  --Sir J.
                                                  Hayward.
      [1913 Webster]

   2. (Law) A warning or citation to appear in court; a written
      notification signed by the proper officer, to be served on
      a person, warning him to appear in court at a day
      specified, to answer to the plaintiff, testify as a
      witness, or the like.
      [1913 Webster]

   3. (Mil.) A demand to surrender.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Summons \Sum"mons\, v. t.
   To summon. [R. or Colloq.] --Swift.
   [1913 Webster]

WordNet (r) 3.0 (2006):

summons
    n 1: a request to be present; "they came at his bidding" [syn:
         bidding, summons]
    2: an order to appear in person at a given place and time
    3: a writ issued by authority of law; usually compels the
       defendant's attendance in a civil suit; failure to appear
       results in a default judgment against the defendant [syn:
       summons, process]
    v 1: call in an official matter, such as to attend court [syn:
         summon, summons, cite]

Moby Thesaurus II by Grady Ward, 1.0:

91 Moby Thesaurus words for "summons":
   Angelus, Angelus bell, alarm, alarum, battle cry, beck,
   beck and call, bid, bid come, biddance, bidding, birdcall,
   bugle call, call, call away, call back, call for, call forth,
   call in, call out, call together, call up, call-up, calling,
   calling forth, certiorari, citation, cite,
   compulsory military service, conjure, conjure up, conscription,
   convene, convocation, convoke, demand, draft, draft call, drafting,
   engraved invitation, enlistment, enrollment, evocation, evoke,
   garnishment, habeas corpus, impressment, indent, induction,
   invitation, invite, invocation, invoke, last post, levy,
   mobilization, monition, moose call, muster, muster up, nod,
   order up, page, preconization, preconize, press, rallying cry,
   rebel yell, recall, recruiting, recruitment, requisition, reveille,
   selective service, send after, send for, serve, subpoena, summon,
   summon forth, summon up, taps, trumpet call, venire,
   venire de novo, venire facias, war cry, warrant, whistle, writ,
   writ of summons



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

SUMMONS, practice. The name of a writ commanding the sheriff, or other
authorized officer, to notify a party to appear in court to answer a
complaint made against him and in the said writ specified, on a day therein
mentioned. 21 Vin. Ab. 42 2 Sell. Pr. 356; 3 Bl. Com. 279.