A nonstandard or dialectal form of 'somewhere,' meaning 'in or to some place that is not known exactly.'
From 'some' plus 'where' plus the emphatic or dialectal '-s.' It's considered informal or regional, similar to 'anywheres' or 'everwheres.'
Somewheres is a perfect example of how dialects and casual speech create words that grammar books reject—millions of people say it, but it remains 'wrong' by formal standards, showing how language rules are really just about power and prestige.
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