Rack up Definition 1 of 2Pro Tip 1/3Negative Undertone The phrase often implies negative connotations when discussing gaining debts or problems. Be careful not to rack up too many parking tickets. Pro Tip 2/3Gradual Process 'Rack up' indicates a gradual increase, not immediate. She gradually racked up enough savings to buy a car. Pro Tip 3/3Casual Expression Used in everyday conversation, but might be too informal for very formal contexts. Over time, I've racked up a nice collection of vinyl records.