Source : Webster's Revised Unabridged Dictionary (1913)

Sinker \Sink"er\, n.
   One who, or that which, sinks. Specifically:
   (a) A weight on something, as on a fish line, to sink it.
   (b) 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 under {Jack}, n.

   {Sinker bar}.
   (a) In knitting machines, a bar to which one set of the
       sinkers is attached.
   (b) In deep well boring, a heavy bar forming a connection
       between the lifting rope and the boring tools, above the
       jars.