*resolvent*

n. [ L. resolvens, p. pr. of resolvere: cf. F. résolvant. See Resolve. ] 1. That which has the power of resolving, or causing solution; a solvent. [ 1913 Webster ]

2. (Med.) That which has power to disperse inflammatory or other tumors; a discutient; anything which aids the absorption of effused products. Coxe. [ 1913 Webster ]

3. (Math.) An equation upon whose solution the solution of a given pproblem depends. [ 1913 Webster ]