The Collaborative International Dictionary of English v.0.48:

Wherein \Where*in"\, adv.
   [1913 Webster]
   1. In which; in which place, thing, time, respect, or the
      like; -- used relatively.
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            Her clothes wherein she was clad.     --Chaucer.
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            There are times wherein a man ought to be cautious
            as well as innocent.                  --Swift.
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   2. In what; -- used interrogatively.
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            Yet ye say, Wherein have we wearied him! --Mal. ii.
                                                  17.
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