DEMONSTRABLY
demonstrably, provably, incontrovertibly
(adverb) in an obvious and provable manner; “his documentary sources are demonstrably wrong”
Source: WordNet® 3.1
Etymology
Adverb
demonstrably (comparative more demonstrably, superlative most demonstrably)
In such a manner as to be capable of being demonstrated, shown or proved.
Source: Wiktionary
De*mon"stra*bly, adv.
Definition: In a demonstrable manner; incontrovertibly; clearly.
Cases that demonstrably concerned the public cause. Clarendon.
DEMONSTRABLE
De*mon"stra*ble, a. Etym: [L. demonstrabilis: cf. OF. demonstrable,
F. démontrable.]
1. Capable of being demonstrated; that can be proved beyond doubt or
question.
The grand articles of our belief are as demonstrable as geometry.
Glanvill.
2. Proved; apparent. [Obs.] Shak.
Source: Webster’s Unabridged Dictionary 1913 Edition