In David Rynin's 1956 address to the American Philosophical Association, "Vindication of L*G*C*L P*S*T*V*SM", he remarks upon the "tenuous logical relationship" between a general statement, "For any substance there exists some solvent" and a singular statement, "Substance A is a soluble in Substance B".
He comments that tho a name is not important, he is at a loss for a suitable name for this kind of logical relationship. Specifically he is pointing out that while the singular statement describes a sufficient condition for the satisfaction of a necessary condition, it does not describe a necessary condition for the general statements necessary condition, and therefore the general statement is not a strictly falsifiable hypothesis.
How then to describe this tenuous relationship?
EDIT: if you register w/Jstor, their basic & free membership allows access to articles (for a limited time, like two weeks iirc). This article by David Rynin (former Professor Emeritus @ UCBerkeley) is one of the ones freely available. Apologies as I am not trying to spam for Jstor, but he is an excellent author and otherwise difficult to find online without co$t.