Dem`on*stra"tion (?), n. [L. demonstratio: cf. F. d'emonstration.]
1.
The act of demonstrating; an exhibition; proof; especially, proof beyond the possibility of doubt; indubitable evidence, to the senses or reason.
Those intervening ideas which serve to show the agreement of any two others are called "proofs;" and where agreement or disagreement is by this means plainly and clearly perceived, it is called demonstration.
Locke.
2.
An expression, as of the feelings, by outward signs; a manifestation; a show.
Did your letters pierce the queen to any demonstration of grief?
Shak.
Loyal demonstrations toward the prince.
Prescott.
3. Anat.
The exhibition and explanation of a dissection or other anatomical preparation.
4.
(Mil.) a decisive exhibition of force, or a movement indicating an attack.
5. Logic
The act of proving by the syllogistic process, or the proof itself.
6. Math.
A course of reasoning showing that a certain result is a necessary consequence of assumed premises; -- these premises being definitions, axioms, and previously established propositions.
Direct, ∨ Positive, demonstration Logic & Math., one in which the correct conclusion is the immediate sequence of reasoning from axiomatic or established premises; -- opposed to Indirect, ∨ Negative, demonstration (called also reductio ad absurdum), in which the correct conclusion is an inference from the demonstration that any other hypothesis must be incorrect.
© Webster 1913.