põlveosa
a shape or size in which ox- or cow-hides are tanned into leather, forming half of a ‘butt'. A ‘butt’ is the entire hide of the back and flanks reduced to a rough rectangle ... When this is cut in two by a line down the middle of the back, before tanning (as is mostly done in Scotland and the north of England), each half is called a ‘bend'. Butts and bends contain the thickest and strongest hide, the qualities of which are further developed by special processes in tanning, so as to make the stoutest leather.