Recalescences

Part of speech: noun

Definitions

1. The brief release of heat that makes iron or steel suddenly warm up while it is being heated through a critical temperature range
2. Sudden temporary increases in temperature seen in iron or steel during heating, caused by a change in its crystal structure
3. Momentary surges of heat observed when iron or steel passes a critical temperature point during the heating process

Etymology: "Recalescences" is the plural of "recalescence", a term from metallurgy for the brief release of heat that some steel gives off as it cools. The noun comes from Latin "recalescere", meaning "to grow warm again", built from the prefix "re-" and "calescere", "to grow warm", an inchoative verb formed from "calere", "to be warm". The Latin root is the same one behind words like "calorie" and "calefaction", the process of making something warm. The English noun is recorded from at least 1873, and the plural form simply counts separate heating episodes, as when a metal passes through the same temperature range more than once during cooling. The sense of the prefix matters here: "re-" signals a repeated warming, which is exactly what happens in the metal.