extender vs lengthener

extender

noun
  • A phrase that extends an expression to include further members of a set, e.g. "and stuff", "or something". 

  • Any of various substances designed to extend any of several properties of a material. 

  • Any substance added to food to bulk it out, with a higher protein content than a filler. 

  • Any of various components designed to extend the length of a device. 

  • A runner, or quick-draw. (from sense #2) 

lengthener

noun
  • A person or thing that lengthens something 

How often have the words extender and lengthener occurred in a corpus of books? (source: Google Ngram Viewer )