Anneal

Part of speech: verb

Pronunciation: /əˈniːl/

Definitions

1. To subject a substance to a controlled heating and cooling regime that enhances its physical properties and relieves internal stresses while improving durability and workability
2. To apply a controlled process of heating and cooling to a material so as to relieve stress and enhance its physical characteristics while improving its durability and flexibility
3. To heat a material and then slowly cool it to reduce internal stress and improve strength and plasticity

Etymology: Anneal is a word that started out as a plain description of fire. Its Old English ancestor, "onǣlan," meant to burn, kindle, or set alight, and it could also be used figuratively for inflaming passions or inspiring someone. The first half, "on," is the ordinary preposition, and the second half, "ǣlan," comes from a Germanic root for burning that also gave modern Icelandic "eldur," Swedish "eld," and Danish "ild," all meaning fire. The metalworking sense came later. Heating a metal until it glows and then letting it cool slowly makes it softer and less brittle, so the old fire-word was applied to that process. The change from burning to controlled heating is a narrowing toward a technical purpose rather than a shift into something unrelated. The spelling with a double "n" is probably an accident of analogy. English had many Latin-derived verbs beginning with "an-" and doubling the consonant, such as "announce," "annex," and "annul," and the form "anneal" was likely reshaped to look like them, even though its real origin lies in Germanic rather than Latin.

Synonyms: heat-treat, treat, temper, condition, refine