[1] : The Collaborative International Dictionary of English v.0.48

shrinking \shrink"ing\,
   a.  n. from shrink.
   1913 webster

   shrinking head founding, a body of molten metal connected
      with a mold for the purpose of supplying metal to
      compensate for the shrinkage of the casting; -- called
      also sinking head, and riser.
      1913 webster
see also:
shrink shrinking head sinking head riser 

[2] : The Collaborative International Dictionary of English v.0.48

sinking \sink"ing\,
   a.  n. from sink.
   1913 webster

   sinking fund. see under fund.

   sinking head founding, a riser from which the mold is fed
      as the casting shrinks. see riser, n., 4.

   sinking pump, a pump which can be lowered in a well or a
      mine shaft as the level of the water sinks.
      1913 webster
see also:
sink sinking fund fund sinking head riser sinking pump 

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