Hyundai Repair: 2002 santa fe - clicking noise, drive belt tensioner, engine crankshaft

Question
i had the belts and water pump changed.  now i'm told i need a belt tensioner for the serpintine drive.  what's the difference between a tensioner and belt tensioner for the serpintine drive

Answer
The term tensioner is generic and can refer to anything that applies tension to any device.  

On your vehicle-- presuming the term serpentine indicates you have the 2.7 V6 engine-- you have a drive belt that runs from the engine crankshaft (main turning component of the engine) pulley around the drive accessories: power steering pump, alternator, and a/c compressor.  This belt is kept tight on these pulleys via a spring-loaded tensioner arm and pulley assembly.  This tensioner is typically referred to as the drive belt tensioner or simply belt tensioner.