geminitudo

A New Latin Dictionary by Charlton T. Lewis Ph.D. and Charles Short, LL. D.

gĕmĭnĭtūdo, ĭnis, f. [geminus],

the difference between twins : habeo ego istam qui distinguam inter vos geminitudinem, i. e. mark , Pac. ap. Non. 116, 18 (Trag. Rel. v. 61 Rib.).