I’m told older English versions render the Greek ἀγάπη as “charity”, not “love”.
We should guard against thinking of love as an archetypal ontic or metaphysical entity. Better to treat it as a disjoint aggregate of related notions. Not an individual had in common, but an explanation for some of our actions. And that seems to be along the lines of what Paul has in mind. Not that I would accept him as an authority.
“What is love?” is best treated not as a request to set out some essential characteristics; there may be no common set of properties held by all instances of love, and in any case understanding that we have the right set of properties implies that we have a way of grasping what love is that is independent of those properties.
See An approach to aesthetics.
Specifically, this post.