thaw / [unvoicedth]ô/ • v. [intr.] (of ice, snow, or another frozen substance, such as food) become liquid or soft as a result of warming: the river thawed and barges of food began to reach the capital | [as n.] (thawing) catastrophic summer floods caused by thawing. ∎  (it thaws, it is thawing, etc.) the weather becomes warmer and melts snow and ice. ∎  [tr.] make (something) warm enough to become liquid or soft: European exporters simply thawed their beef before unloading. ∎  (of a part of the body) become warm enough to stop feeling numb: Ryan began to feel his ears and toes thaw out. ∎  become friendlier or more cordial: she thawed out sufficiently to allow a smile to appear. ∎  [tr.] make friendlier or more cordial: the cast thawed the audience into real pleasure.• n. a period of warmer weather that thaws ice and snow: the thaw came yesterday afternoon. ∎  an increase in friendliness or cordiality: a thaw in relations between the U.S.A. and Iran.

thaw reduce to a liquid state OE.; intr. XIV. OE. þawian = MLG dōien, Du. dooien, OHG. douwen :- WGmc. *þawōjan (cf. ON. þeyja :- *þaujan), of unkn. orig.
Hence sb. XV.

thaw Onset of melting of ice and snow as the temperature rises above the freezing point.