'Effector' definitions:

Definition of 'effector'

From: WordNet
noun
One who brings about a result or event; one who accomplishes a purpose [syn: effecter, effector]
noun
A nerve fiber that terminates on a muscle or gland and stimulates contraction or secretion
noun
An organ (a gland or muscle) that becomes active in response to nerve impulses [ant: receptor, sense organ, sensory receptor]

Definition of 'Effector'

From: GCIDE
  • Effector \Ef*fect"or\, n. [L.] An effecter. --Derham. [1913 Webster]