Resistors, slow current. They "resist" it. If they stopped current, they would be called Stopistors. (or Switches.)
Some lucky company's marketing department is really missing the boat is they don't now quickly come out with a new line of Stopistors in various colors and sizes. Switches are so 2010. 
Resistors also can't 'slow' current, but rather reduce current. Otherwise they would call them Slowistors.
Lefty