'Vergency' definitions:

Definition of 'Vergency'

From: GCIDE

Vergency \Ver"gen*cy\, n.
1. The act of verging or approaching; tendency; approach. [R.] [1913 Webster]
2. (Opt.) The reciprocal of the focal distance of a lens, used as measure of the divergence or convergence of a pencil of rays. [R.] --Humphrey Lloyd. [1913 Webster]