Your paycheck is the money you get from work, usually every week or two. Country singer Johnny Paycheck’s big hit was “Take This Job and Shove It.” Good luck getting a paycheck after saying that!
An employer usually pays employees with regularly scheduled paychecks. Your paycheck represents payment of your wages for the amount of time you worked. A lot of workers have their salaries deposited directly into their bank accounts, so they don't actually get a paper paycheck. You can also use paycheck more generally to mean "income" or "earnings," as in "All that money for health insurance comes right out of my paycheck."