The Collaborative International Dictionary of English v.0.48:

Embarkation \Em`bar*ka"tion\, n.
   1. The act of putting or going on board of a vessel; as, the
      embarkation of troops.
      [1913 Webster]

   2. That which is embarked; as, an embarkation of Jesuits.
      --Smollett.
      [1913 Webster]

WordNet (r) 3.0 (2006):

embarkation
    n 1: the act of passengers and crew getting aboard a ship or
         aircraft [syn: boarding, embarkation, embarkment]
         [ant: debarkation, disembarkation, disembarkment]