CONVERGENCY
convergence, converging, convergency
(noun) the act of converging (coming closer)
convergence, convergency
(noun) the approach of an infinite series to a finite limit
Source: WordNet® 3.1
Noun
convergency (countable and uncountable, plural convergencies)
Alternative form of convergence
Source: Wiktionary
Con*ver"gence, Con*ver"gen*cy, n. Etym: [Cf. F. convergence.]
Definition: The condition or quality of converging; tendency to one point.
The convergence or divergence of the rays falling on the pupil.
Berkeley.
Source: Webster’s Unabridged Dictionary 1913 Edition