1. n. [Formation Evaluation]

The device that connects the end of the logging cable or the bridle to the top of the logging tool. It contains the weak point, so that when the weak point is broken and the cable removed, the uppermost assembly left in the hole is the head. The top of the head is specially designed to ease fishing of the logging tool, and is also known as the fishing bell.

Alternate Form: fishing bell

See: logging tool