A variant or dialectal spelling of 'aught' or an exclamation expressing surprise or confusion.
This appears to be a very rare or archaic variant, possibly dialectal or misspelled. The exact etymology is unclear, as 'auh' is not standard in modern English dictionaries.
Extremely obscure words like 'auh' remind us that language history is full of dead branches—words that existed in some dialect or text but never caught on, leaving us wondering what people meant and why they wrote it that way.
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