Annealing \An*neal"ing\, n.

1. The process used to render glass, iron, etc., less brittle, performed by allowing them to cool very gradually from a high heat.

2. The burning of metallic colors into glass, earthenware, etc.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Anneal \An*neal"\, v. t. [imp. & p. p. Annealed; p. pr. & vb. n. Annealing.]

[OE. anelen to heat, burn, AS. an?lan; an on + ?lan to burn; also OE. anelen to enamel, prob. influenced by OF. neeler, nieler, to put a black enamel on gold or silver, F. nieller, fr. LL. nigellare to blacken, fr. L. nigellus blackish, dim. of niger black. Cf. Niello, Negro.]

1. To subject to great heat, and then cool slowly, as glass, cast iron, steel, or other metal, for the purpose of rendering it less brittle; to temper; to toughen.

2. To heat, as glass, tiles, or earthenware, in order to fix the colors laid on them.

Source: Webster's Revised Unabridged Dictionary (1913)