Dialectal or regional variation meaning 'by and by' or 'soon' or 'presently'—by and by.
From English 'by' and 'by' (meaning later or soon), contracted and dialectalized into 'bimeby.' Common in historical regional dialects, particularly in African American Vernacular English and Southern American English.
This word is a time-traveler—it's how people actually said 'soon' in historical American speech, and it shows that what we call 'slang' or 'dialect' is often just how real people communicate when linguists aren't watching.
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