What is solidifying?

Some articles on solidifying:

Agar - Background
... Agar exhibits hysteresis, melting at 85 °C (358 K, 185 °F) and solidifying from 32-40 °C (305-313 K, 90-104 °F) ... (37 °C), agar is more appropriate than other solidifying agents that melt at this temperature, such as gelatin ... He discovered that it was more useful as a solidifying agent than gelatin, due to its better solidifying temperature ...
Solder Alloys - Solidifying
... The solidifying behavior depends on the alloy composition ... Pure metals solidify at a sharply defined temperature, forming crystals of one phase ...