"Pure leather" is commonly used in furniture marketing to distinguish genuine leather from synthetic alternatives. However, it is not a precise industry grading term and does not by itself indicate whether the leather is full-grain, top-grain or corrected-grain.
Genuine leather can vary considerably in quality depending on the hide, tanning process, finishing, thickness and surface treatment.
When comparing leather furniture, it is more useful to ask about the specific leather type and which parts of the furniture use genuine leather.