Answer
The purchases ledger (creditors ledger or accounts payable ledger) contains a personal account for each credit supplier, showing invoices (credits), and returns, payments, and discounts (debits), and the balance owed to them. Like the sales ledger, it's a memorandum ledger reconciled to the purchases ledger control account.
Real-world example Each supplier has an account in the purchases ledger showing amounts owed and paid.