One who, or that which, sinks. Specifically:
In knitting machines, one of the thin plates, blades, or other devices, that depress the loops upon or between the needles. Dividing sinker, in knitting machines, a sinker between two jack sinkers and acting alternately with them. Jack sinker. See Jack, Sinker bar. In knitting machines, a bar to which one set of the sinkers is attached. In deep well boring, a heavy bar forming a connection between the lifting rope and the boring tools, above the jars.