The Collaborative International Dictionary of English v.0.48:

Seizin \Sei"zin\, n. [F. saisine. See Seize.]
   1. (Law) Possession; possession of an estate of froehold. It
      may be either in deed or in law; the former when there is
      actual possession, the latter when there is a right to
      such possession by construction of law. In some of the
      United States seizin means merely ownership. --Burrill.
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   2. The act of taking possession. [Obs.]
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   3. The thing possessed; property. --Sir M. Halle.
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   Note: Commonly spelt by writers on law seisin.
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   Livery of seizin. (Eng. Law) See Note under Livery, 1.
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