anneal

1. (metallurgy) To subject to great heat and then (often slow) cooling, and sometimes reheating and further cooling, for the purpose of rendering less brittle; to temper; to toughen.Examples: "The best tough soft iron, such as will weld round, is drawn into rods by smiths, using charcoal fires, and taking welding heats every time, the rod is about 1.4 inch diameter, 9 or 10 feet long, containing 4lbs. each, tapered at each end to a long point; they are first anealed by being brought to a bright red heat, in a furnace excluding the air as much as possible, for if the air can be entirely excluded, no scab will rise in anealing; […]"; "On closer inspection it appeared that steel annealed at 100° is, cæteris paribus, more easily soluble than glass hard steel; steel annealed at 200° more easily soluble than steel annealed at 100°, and steel annealed at 360° more easily soluble than steel annealed at 200°. […] These curious results were substantiated by annealing one-half of short glass hard rods (ca. 5ᶜᵐ in length) at red heat on dissolving in HCl, the diameter of the soft length is diminished more rapidly than the diameter of the hard length."; "The isolated disordered regions and the amorphous layer have widely different anneal behavior. In the case of germanium and silicon, the isolated disordered regions anneal at moderate temperatures of approximately 200° and 300° C, respectively. The amorphous layers also anneal in a characteristic fashion, but at appreciably higher temperatures, i.e., at approximately 600° C in silicon and 400° C in germanium. It should be noted that even though both types of disorder can be annealed at temperatures well below those where diffusion of the dopant species occurs, there are still defects present."

2. (archaic) To burn colors onto a glass or other surface.Examples: "It was customary to beautify the Prow with Gold, and various ſorts of Paint and Colours: […] Several other Colours were alſo made uſe of, nor were they barely varniſh'd over with them, but very often anneal'd by Wax melted in the Fire, ſo as neither the Sun, Winds, or Water were able to deface them."; "Such were the features of her heavenly Face, / Her limbs were form'd with ſuch harmonious grace: / So faultleſs was the frame, as if the whole / Had been an emanation of the ſoul; / Which her own inward ſymmetry reveal'd; / And like a picture ſhone, in glaſs anneal'd."archaic

3. (genetics, ambitransitive) To make a double-stranded nucleic acid by pairing a single strand with a complementary strand.Examples: "The 5′ junction is checked using a target gene-specific primer of ~21 nucleotides, which anneals upstream of the cassette integration site, together with a primer which anneals downstream of the first loxP site in the PCR cassette."ambitransitive

4. (figurative, archaic or poetic) To strengthen or harden.Examples: "The experience annealed them, strengthening their resolve."Synonyms: induratearchaicfigurativelypoetic