S / sumptio
noun

sumptio

gen. sumptōnis · gender feminine · decl. 3rd
(collat. form , Cato, R. R. 145, 2), , sumo
a taking
a taking.
Lit., Vitr. 1, 2, 2.—
a premise taken for granted; an assumption figuratively
Trop., in logic, a premise taken for granted, an assumption: demus tibi istas duas sumptiones, ea quae λήμματα appellant dialectici; sed nos Latine loqui malumus, Cic. Div. 2, 53, 108.