Source : Webster's Revised Unabridged Dictionary (1913)

Subinfeudation \Sub*in`feu*da"tion\, n. (Law)
   (a) The granting of lands by inferior lords to their
       dependents, to be held by themselves by feudal tenure.
       --Craig.
   (b) Subordinate tenancy; undertenancy.

             The widow is immediate tenant to the heir, by a
             kind of subinfeudation, or undertenancy.
                                                  --Blackstone.