ANNEAL

verb Etymology: Middle English anelen to set on fire, from Old English onǣlan, from on + ǣlan to set on fire, burn, from āl fire; akin to Old English ǣled fire, Old Norse eldr Date: 1664 transitive verb 1. to heat and then cool (as steel or glass) usually for softening and making less brittle, to heat and then cool (double-stranded nucleic acid) in order to separate strands and induce combination at lower temperature with complementary strands, strengthen , toughen , intransitive verb to be capable of combining with complementary nucleic acid by a process of heating and cooling