The Collaborative International Dictionary of English v.0.48:

Subjugation \Sub`ju*ga"tion\, n. [Cf. F. subjugation, LL.
   subjugatio.]
   The act of subjugating, or the state of being subjugated.
   [1913 Webster]

WordNet (r) 3.0 (2006):

subjugation
    n 1: forced submission to control by others [syn: subjugation,
         subjection]
    2: the act of subjugating by cruelty; "the tyrant's oppression
       of the people" [syn: oppression, subjugation]
    3: the act of conquering [syn: conquest, conquering,
       subjection, subjugation]