The Collaborative International Dictionary of English v.0.48:

Pollicitation \Pol*lic`i*ta"tion\, n. [L. pollicitatio, fr.
   pollicitari to promise, v. intens. fr. polliceri to promise:
   cf. F. pollicitation.]
   1. A voluntary engagement, or a paper containing it; a
      promise. --Bp. Burnet.
      [1913 Webster]

   2. (Roman Law) A promise without mutuality; a promise which
      has not been accepted by the person to whom it is made.
      --Bouvier.
      [1913 Webster]

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

POLLICITATION, civil law. A pollicitation is a promise not yet accepted by
the person to whom it is made; it differs from a contract inasmuch as the
latter includes a concurrence of intention in two parties, one of whom
promises something to the other, who accepts on his part of such promise. L.
3, ff. Pollicit.; Grotius, lib. 2, c. 2; Poth. on Oblig. P. 1, c. 1, s. 1,
art. 1,Sec. 2.
     2. An offer to guaranty, but not accepted, is not a contract on which
an action will lie. 1 Stark. C. 10; 1 M. & S. 557; 3 B. & C. 668, 690; 5 D.
& R. 512, 586; 7 Cranch, 69; 17 John. R. 134; 1 Mason's R. 323, 371; 16
John. R. 67; 3 Conn. R. 438; 1 Pick. R. 282, 3; 1 B. & A. 681.