The Collaborative International Dictionary of English v.0.48:

Solvency \Sol"ven*cy\ (s[o^]l"ven*s[y^]), n. [See Solvent.]
   The quality or state of being solvent.
   [1913 Webster]

WordNet (r) 3.0 (2006):

solvency
    n 1: the ability to meet maturing obligations as they come due
         [ant: insolvency]

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

SOLVENCY. The state of a person who is able to pay all his debts; the
opposite of insolvency. (q.v.)