Definition from Wiktionary, the free dictionary
extender (plural extenders)
- Any of various substances designed to extend any of several properties of a material.
- Any of various components designed to extend the length of a device.
- (climbing) Another term for runner or quick-draw. (from sense #2)
Derived terms 
- to extend
Conjugation of extender (See Appendix:Spanish verbs)
Rule: e becomes ie in stressed syllables.