demonstrable (adj.)

"capable of being proved or made evident beyond doubt," c. 1400, from Old French demonstrable and directly from Latin demonstrabilis, from demonstrare "to point out, indicate, demonstrate," figuratively, "to prove, establish," from de- "entirely" (see de-) + monstrare "to point out, show," from monstrum "divine omen, wonder" (see monster). Related: Demonstrably.