The Collaborative International Dictionary
Vadium
Vadium \Va"di*um\, n. [LL., from L. vas, vadis, bail.] (Law) Pledge; security; bail. See Mortgage.
Vadium vivum [LL.] (Law), a living pledge, which exists where an estate is granted until a debt is paid out of its proceeds.
Wiktionary
vadium
n. (context legal archaic English) A pledge or security; bail.