Annular Packoff 2 : A mechanism that seals off annular pressure between the OD of a suspended tubular member or hanger and the ID of the head or thru spool which the tubular member passes or hanger is suspended. (Spec 6A)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}