Internal Revenue Service (IRS): The U.S. government agency responsible for tax collection and tax law enforcement; think of them as the strict teacher who makes sure everyone turns in their homework on time.
Tax Evasion: Illegal practice where an individual, corporation, or organization intentionally avoids paying their true tax liability; this would be like trying to sneak out of class without turning in your assignment.
Tax Return: A form(s) filed with a taxing authority that reports income, expenses, and other pertinent tax information; it's like filling out a detailed report about how you spent your time studying for an exam.