sinker
1. a weight attached to a fishing line, net, etc., to cause it to sink in water
2. a person who sinks shafts, etc.
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
sinker
[′siŋ·kər] (mining engineering)
A person who sinks mine shafts and puts in framing.
A special movable pump used in shaft sinking.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.