1heat (metal or glass) and allow it to cool slowly, in order to remove internal stresses and toughen it:copper tubes must be annealed after bending or they will be brittle (as adjective annealing)the chimneys of annealing furnaces figurativeDr Lowenstein, annealed to hostility, looked at me coolly
2 Biochemistry recombine (DNA) in the double-stranded form.