Wordnet 3.0
NOUN (1)
1.
(reduction to the absurd) a disproof by showing that the consequences of the proposition are absurd;
or a proof of a proposition by showing that its negation leads to a contradiction;
[syn: reductio ad absurdum, reductio]
WordNet (r) 3.0 (2006):
reductio
n 1: (reduction to the absurd) a disproof by showing that the
consequences of the proposition are absurd; or a proof of a
proposition by showing that its negation leads to a
contradiction [syn: reductio ad absurdum, reductio]