Wadset

from The Collaborative International Dictionary of English v.0.48

Wadset \Wad"set\, n. [Scot. wad a pledge; akin to Sw. vad a
   wager. See {Wed}.] (Scots Law)
   A kind of pledge or mortgage. [Written also {wadsett}.]
   [1913 Webster]

from Bouvier's Law Dictionary, Revised 6th Ed (1856)

WADSET, Scotch law. A right, by which lands, or other heritable subjects, 
are impignorated by the proprietor to his creditor in security of his debt; 
and, like other heritable rights, is perfected by seisin. 
     2. Wadsets, by the present practice, are commonly made out in the form 
of mutual contracts, in which one party sells the land, and the other 
grants, the right of reversion. Ersk. Pr. L. Scot., B. 2, t. 8, s. 1, 2. 
     3. Wadsets are proper or improper. Proper, where the use of the land 
shall go for the use of the money. Improper, where the reverser agrees to 
make up the deficiency; and where it amounts to more, the surplus profit of 
the land is applied to the extinction of the principal. Id. B. 2, t. 8, s. 
12, 13.