My favorite jelly comes from high Sierra gooseberries, a thorny "ribe," a relative of currants. The taste is more delicate than black or red currant jelly, but quite pronounced in its own way. I once proposed writing a musical paean to this noble fruit, but came up short. The rare jelly turned out to be a quickly vanishing muse.
I think we, in the U.S. and those in the U.K. are speaking basically the same language in this case. Jelly is clear and jelled with fruit pectin, where jam is a whole or macerated fruit spread. Jell-O' a totally unrelated "delicacy," is (often artificially) flavored water, sugar and animal-based gelatin, served in hospitals, school cafeterias and prisons to captive audiences.