The Collaborative International Dictionary of English v.0.48:

Assignation \As`sig*na"tion\, n. [L. assignatio, fr. assignare:
   cf. F. assignation.]
   1. The act of assigning or allotting; apportionment.
      [1913 Webster]

            This order being taken in the senate, as touching
            the appointment and assignation of those provinces.
                                                  --Holland.
      [1913 Webster]

   2. An appointment of time and place for meeting or interview;
      -- used chiefly of love interviews, and now commonly in a
      bad sense.
      [1913 Webster]

            While nymphs take treats, or assignations give.
                                                  --Pope.
      [1913 Webster]

   3. A making over by transfer of title; assignment.
      [1913 Webster]

   House of assignation, a house in which appointments for
      sexual intercourse are fulfilled.
      [1913 Webster]

WordNet (r) 3.0 (2006):

assignation
    n 1: a secret rendezvous (especially between lovers) [syn:
         assignation, tryst]
    2: the act of distributing by allotting or apportioning;
       distribution according to a plan; "the apportionment of seats
       in the House of Representatives is based on the relative
       population of each state" [syn: allotment, apportionment,
       apportioning, allocation, parceling, parcelling,
       assignation]

Moby Thesaurus II by Grady Ward, 1.0:

112 Moby Thesaurus words for "assignation":
   abalienation, accounting for, agreement, alienation, amortization,
   amortizement, answerability, application, appointment, arrangement,
   arrogation, ascription, assemblee, assembly, assignation house,
   assignment, at home, attachment, attribution, ball,
   bargain and sale, barter, bequeathal, blame, brawl, caucus,
   cession, charge, colloquium, commission, committee, conclave,
   concourse, conferment, conferral, congregation, congress,
   connection with, consignation, consignment, conventicle,
   convention, conveyance, conveyancing, convocation, council, credit,
   dance, date, deeding, deliverance, delivery, demise,
   derivation from, diet, disposal, disposition, eisteddfod,
   enfeoffment, etiology, exchange, festivity, fete, forgathering,
   forum, gathering, get-together, giving, honor, housewarming,
   imputation, lease and release, levee, love nest, meet, meeting,
   meeting place, palaetiology, panel, party, place of assignation,
   placement, plenum, prom, quorum, rally, reception, reference to,
   rendezvous, responsibility, saddling, sale, seance, session,
   settlement, settling, shindig, sit-in, sitting, soiree, surrender,
   symposium, synod, trading, transfer, transference, transmission,
   transmittal, tryst, turnout, understanding, vesting



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

ASSIGNATION, Scotch law. The ceding or yielding a thing to another of which
intimation must be made.