loaf

A loaf is a whole shaped mass of baked bread. Before it is cut, it is a loaf; afterwards it is slices.

The plural is loaves, following the same pattern as leaf and knife. English names the shapes: a tin loaf, a cottage loaf, a bloomer. There is a completely separate verb meaning to idle about doing nothing, so loafing around is a mild reproach, and a loafer is both an idler and a kind of slip-on shoe. British slang also uses your loaf for your head, as in use your loaf.