APR: the interest rate charged by a creditor when you carry a balance; cards often offer low APRs for new accounts, but these rates can rise sharply after a single missed or late payment
Credit Report: a formal record of your borrowing; shows every account opened and closed, full payment history, and available credit limits; you get (and absolutely should review!) a free credit report each year from AnnualCreditReport.com

Credit Score: a three digit rating based on your credit history used to determine interest rates and eligibility for future loans (including apartment leases); a “good” credit score starts around 670
Fixed vs Variable Expenses: when you budget, deduct fixed expenses first (rent, utilities, insurance), then allocate what’s left for variable ones (gas, groceries, entertainment); don’t forget to put something aside for savings.

Gross vs Net Income: gross income is your total before taxes, insurance, and any retirement contributions; net income is your actual take-home pay

Withholding: the amount held back from your paycheck for Medicare and Social Security; setting to 1 results in smaller paychecks but a potentially larger tax refund, while setting to 0 puts more in your pocket each payday but may result in more tax owed