Hook Block : Block with hook attached used in lifting service. It may have a single sheave for double or triple line or multiple sheaves for four or more parts of line. (Spec 2C)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}