An archaic form referring to a pledge, surety, or a person who provides security or guarantee for another.
From Old English 'borh' or 'byrh', related to 'borg' (pledge, security), from Proto-Germanic 'burg' roots meaning to protect or provide security.
In medieval times, your 'borh' was more important than your bank—a person stood as living collateral for your good behavior, so betraying them socially meant destruction for an innocent third party.
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