A label that says "genuine leather" is technically true and practically unhelpful. It confirms the material is real leather and tells you nothing about which part of the hide it came from — which is the part that decides how it wears.
What the terms actually describe
Full-grain: the intact top surface of the hide. Strongest fibres, natural markings, ages by softening and darkening.
Top-grain: the top layer with its surface sanded and recoated. Uniform, thinner, and less able to develop character.
Genuine leather: an umbrella term, frequently the split — the lower layer left after the grain is separated off — finished with a sprayed or embossed surface.
Bonded leather: reconstituted scraps and dust glued to a backing. Real leather content, minimal leather performance.
The quiet tell
Marketing leans on "genuine" precisely because it sounds like a guarantee. When a maker is proud of the grade, they name it — full-grain, and the hide it came from. When they aren't, they reach for the vaguest word available. We name ours: full-grain sheep leather. If a tag won't tell you the grade, treat the omission as the answer.