Definition of extenders:
(n) :
One who extends.
(n) :
Any of various components designed to extend the length of a device.
(n) :
Any of various substances designed to extend any of several properties of a material.
(n) :
Any substance added to food to bulk it out, with a higher protein content than a filler.
(n) :
(climbing) A runner, or quick-draw.
(n) :
(linguistics) A phrase that extends an expression to include further members of a set, e.g. "and stuff", "or something".