Sinker
Sinker turns up in 2 fields: lighting, woodworking. Here is what it means to the people in each one.
Sinker in lighting
A piece of hardware or stand that slowly loses its height because of a worn friction lock.
A lighting stand, boom, or music stand that cannot maintain its set height and slowly slides downward under a load. This is typically caused by stripped threading, worn friction collars, or over-tightened clutches that no longer grip the inner pipe. Sinkers are a major nuisance on set because they ruin precise focus calls and can be dangerous if a heavy luminaire drops suddenly.
"Grab a roll of gaff tape to lock off this stand, the clutch is totally shot and it's a sinker."
Sinker in woodworking
A framing nail with a textured head and a smooth shank coated in vinyl or resin.
A sinker is a specific type of framing nail designed to drive easily and hold fast. It features a slightly smaller, checkered head to prevent the hammer from slipping, and a shank coated with a heat-activated resin. The friction of being driven melts the coating, which acts as a lubricant on the way in and an adhesive once cooled.
"Grab a box of sixteen-penny sinkers for these wall plates."