is a specific kind of: commerce, commercialism, mercantilism.

is a broader term that covers: amortisation, amortization | fee splitting | overpayment | prepayment | ransom | refund, repayment | remuneration | rendering | disbursal, disbursement, outlay, spending | tribute | underpayment ... show more.

is the opposite of: evasion, nonpayment.

derivation: pay | ante up, pay, pay up | pay | defray.