\Hy`po*the"ca\, n. [L., fr. Gr. ? a thing subject to
some obligation, fr. ? to put under, put down, pledge. See
{Hypothesis}.] (Rom. Law)
An obligation by which property of a debtor was made over to
his creditor in security of his debt.
Note: It differed from pledge in regard to possession of the
      property subject to the obligation; pledge requiring,
      simple hypotheca not requiring, possession of it by the
      creditor. The modern mortgage corresponds very closely
      with it. --Kent.