Definify.com
Webster 1913 Edition
Devitrification
De-vitˊri-fi-ca′tion
,Noun.
The act or process of devitrifying, or the state of being devitrified. Specifically, the conversion of molten glassy matter into a stony mass by slow cooling, the result being the formation of crystallites, microbites, etc., in the glassy base, which are then called devitrification products.