A rare or non-standard abbreviation, possibly for 'drench' or 'dreich', though this is not standard in modern English.
If abbreviation, would derive from the word it represents. As presented, this appears to be a typo, partial word, or non-standard orthography.
Drch appears to be either a typo or extremely archaic shorthand—modern abbreviations tend to be more systematic, so this word's presence in a word list suggests you may have caught a database error.
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