People or companies that send bills or invoices to customers for payment of services or goods.
From 'bill' (a written statement of charges) plus the agent suffix '-er' (one who does), with plural '-s'. The word 'bill' comes from Middle English and Latin 'billa', originally meaning a written document or note.
The word 'biller' is relatively modern—it exploded in usage during the 20th century as automated billing systems became crucial to hospitals, utilities, and credit card companies, creating an entire profession dedicated to the paperwork of money.
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