The Collaborative International Dictionary of English v.0.48:

Promulgation \Pro`mul*ga"tion\, n. [L. promulgatio: cf. F.
   promulgation.]
   The act of promulgating; publication; open declaration; as,
   the promulgation of the gospel. --South.
   [1913 Webster]

WordNet (r) 3.0 (2006):

promulgation
    n 1: a public statement containing information about an event
         that has happened or is going to happen; "the announcement
         appeared in the local newspaper"; "the promulgation was
         written in English" [syn: announcement, promulgation]
    2: the official announcement of a new law or ordinance whereby
       the law or ordinance is put into effect
    3: the formal act of proclaiming; giving public notice; "his
       promulgation of the policy proved to be premature" [syn:
       proclamation, promulgation]

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

PROMULGATION. The order given to cause a law to be executed, and to make it
public it differs from publication. (q.v.) 1 Bl. Com. 45; Stat. 6 H. VI., c.
4.
     2. With regard to trade, unless previous notice can be brought home to
the party charged with violating their provisions, laws are to be considered
as beginning to operate in the respective collection districts only from the
time they are received from the proper department by the collector. Paine's
C. C. R. 32. See Paine's C. C. R. 2 3.