Cut of pork
(Other definitions for spare rib that I've seen before include "Only a little pork on this bone" , "Pork joint" , "Adam, apparently, had one" , "Bony pork serving" , "Meat on the bone, perhaps in barbecue sauce" .)
'cut of pork' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for loin that I've seen before include "Cut of meat from between rib and haunch" , "Part of the body to which "lumbar" refers" , "Lumbar region" , "Choice cut of meat" , "Joint of meat" .)