Unciatim | Webster's Dictionary of the English Language

unciatim
uncĭātim, adv. [uncia], by twelfths, by ounces. * I Lit.: (axungia) datur et phthisicis unciatim, ...

A New Latin Dictionary by Charlton T. Lewis Ph.D. and Charles Short, LL. D.
unciatim
unciātim adv. uncia, by twelfths, by ounces ; hence, little by little : Quod ille unci...

An Elementary Latin Dictionary