The term 'Singles in a Wallet' can be broken down into two crossword solutions: 'ONES' (4 letters). This phrase is often used to refer to one-dollar bills, which are the smallest denomination of paper currency in the United States. These bills are commonly referred to as 'singles' because they are worth one dollar each. The phrase 'in a wallet' implies that these singles are being stored in a wallet, which is a small, flat case used to carry money and other small personal items.