— summability , n.
/sum"euh beuhl/ , adj. Math.
1. capable of being added.
2. (of an infinite series, esp. a divergent one) capable of having a sum assigned to it by a method other than the usual one of taking the limit of successive partial sums.
3. (of a function) possessing a finite Lebesgue integral.
[ 1775-85; SUM + -ABLE ]