This a T-shaped bone found in a sheep's head which was worn round the neck or carried in a pocket to bring luck, or as a protection against witches. First mentioned under that name in Northamptonshire in 1851 (Sternberg, 1851: 154), nearly all the other 19th-century references to the bone are from the northern counties, although elsewhere a pig's bone seems to have had a similar use. Letters in N&Q (3s:9 (1866), 59, 146) mention a pig's head bone carried as a charm in Cornwall, and a newspaper advertisement from a quack doctor in July 1764: ‘I do give two pence for the little round bone in a pig's skull; it lies inside between the eye and ear’. The sheep bone's shape has led some folklorists to speculate that its similarity to the cross explains its presumed efficacy.
Compare BONES, CRAMP.
Opie and Tatem, 1989: 234.