Plural of hackney; horses for hire, taxi cabs, or things that have become trite and overused.
From Hackney, a district in London that became famous for renting out horses. The name shifted from a place to a type of horse to a general term for anything commonly used and worn out.
Hackney, London, accidentally became immortal in the English language—a neighborhood's name stuck because their rental horses were so ubiquitous that 'hackney' became synonymous with cheapness and overuse.
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