n.1.The quantity of being addible; capability of addition.
Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in periodicals archive ?
[Y]ou might as well try to add 20 apples to 20 pears.'" He argued, however, that "[t]his addibility of the happiness of different subjects" was a necessary starting point for political reasoning.