Ouster \Oust"er\, n. [Prob. fr. the OF. infin. oster, used substantively. See Oust.]

A putting out of possession; dispossession; ejection; disseizin.

Ouster of the freehold is effected by abatement, intrusion, disseizin, discontinuance, or deforcement. --Blackstone.

Ouster le main. [Ouster + F. la main the hand, L. manus.]

(Law) A delivery of lands out of the hands of a guardian, or out of the king's hands, or a judgement given for that purpose. --Blackstone.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Dispossession \Dis`pos*ses"sion\, n. [Cf. F. d['e]possession.]

1. The act of putting out of possession; the state of being dispossessed. --Bp. Hall.

2. (Law) The putting out of possession, wrongfully or otherwise, of one who is in possession of a freehold, no matter in what title; -- called also ouster.

Source: Webster's Revised Unabridged Dictionary (1913)