Temper steel by heating & cooling

verb

1. To heat and then cool (a material, such as steel or glass) usually for softening and making less brittle

   "Each bar, with its intricate twists, bevels and turns, had to be shaped individually. This shaping made some parts of the bars brittle … . To restore their flexibility, all the bars had to be annealed by heating, and then rapidly cooling them."

2. To cause two complementary strands of nucleic acid (such as DNA or RNA) to join by hydrogen bonding

   "During repair of DNA double-strand breaks, cells must accurately anneal broken strands …"

3. Strengthen, toughen
4. To pair with a complementary strand of nucleic acid

   "A microRNA molecule can anneal to a messenger RNA (mRNA) containing a nucleotide sequence that complements the sequence of the microRNA …"

5. Strengthen, toughen

   "Mildred at least, is capable of love. In Veda, love has been annealed to a hard diamond of ambition."