Wiktionary
adv. 1 According to, or as a matter of, definition. 2 Necessarily; always; certainly.
Usage examples of "by definition".
To be here today by definition means to have survived, whether as dung beetle, mushroom, or human.
Putting an enemy in such a position was an error, for a man who has nothing to lose is, by definition, risking nothing to obtain what he desires.
It is by definition a solitary vice, and all the public usually gets to see is a sheeted figure being carried out to the wagon.
The latter enjoyed constructing roads, but could not be trusted - the Turks never promised us anything, and therefore were by definition incapable of perfidy - and the British were worse than the Turks for some of the time, and the best of all of them for the rest.
I merely observed that, on the basis of galactic history, genetic engineering and the selective breeding of sentient beings cannot be considered socially irresponsible by definition.