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Webster 1828 Edition

ppr.

Dissolving; resolving into a fluid; liquefying; as any thing frozen.

thawing

thawing ‎(plural thawings)

The process by which something thaws.
- 1829, James Macauley, The natural, statistical, and civil history of the state of New York
  Hence, there is a succession of thawings and freezings. The former expand, and endeavour to restore the surface of the ground to its natural condition, while the latter contract and harden it.