1. Also effecter. a person or thing that effects.
  2. Physiology. an organ or cell that carries out a response to a nerve impulse.
  3. Biochemistry. a substance, as a hormone, that increases or decreases the activity of an enzyme.

Origin of effector

1595–1605; < Latin, equivalent to effec- variant stem of efficere (see effect) + -tor -tor
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for effector



  1. physiol a nerve ending that terminates in a muscle or gland and provides neural stimulation causing contraction or secretion
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

effector in Medicine


  1. A muscle, gland, or organ capable of responding to a stimulus, especially a nerve impulse.
  2. A nerve ending that carries impulses to a muscle, gland, or organ and activates muscle contraction or glandular secretion.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.