1) A pin which could be inserted through a hole in order to secure something such as a bolt: they were typically made of iron and used frequently in connection with church bells.
1544 for makyng of 5 yron bolts with their coterells, Hilderthorpe
1573 a cotterell to the little bell, 1d, York
1595 for sex cotterills for the bells, 12d, Howden
1665 Nich: Atkinson pro bolt & the cotterill of the little carriage, Ripon Minster
1727 nineteen iron tenter pins, one iron cotterall, one iron sadle plate, Sowerby. In his Farming Book, Henry Best described the use of cotterels in the building of sheep folds: 1642 The 5th thinge belonging to a barre is Cotterills, which ... serve instead of pinnes, beinge something like unto wood-pinnes but they have a notch in the midst, that they beinge once knock’d in they cannot come forth again, Elmswell.