Means, in relation to any ETR (point 2.03 below), as applicable, any and all contracts, understandings, instruments, agreements, invoices, refunds, notes, purchase orders, accounts receivable, payment obligations, Letter of Credit, promissory note, payment by installments, lease payment obligations or other writings (including an agreement evidenced by a purchase order or similar document) pursuant to or under which a Person becomes or is obligated to make payment in respect of such ETR