Source : Webster's Revised Unabridged Dictionary (1913)

Effector \Ef*fect"or\, n. [L.]
   An effecter. --Derham.

Source : WordNet®

effector
     n 1: one who brings about a result or event; one who accomplishes
          a purpose [syn: {effecter}]
     2: a nerve fiber that terminates on a muscle or gland and
        stimulates contraction or secretion
     3: an organ (a gland or muscle) that becomes active in response
        to nerve impulses [ant: {sense organ}]