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Barrio (2) m. (Surname) meaning unknown (possibly "the countryside," "the new place")
Of uncertain, but probably Basque origin, as the surname is endemic to Basque people and the ending -o looks like the locative suffix. Perhaps meaning "the countryside" or "the new place," from Barri with the locative suffix -o. (See Barri for an explanation of the debate surrounding this word's origin.)

The belief that the surname is from barrio (1) in the sense of "neighborhood" is an old myth from folk etymology.