Lewis & Short

con-germānesco, ĕre, v. inch. n. [germanus], to grow together with one, grow up with: coalescere, conjungi vel consociari, Non. p. 90, 16 sq. (ante- and post-class., and very rare): cum illis, Quadrig. ap. Non. l. l.; so, mecum, App. M. 2, p. 119, 14.