reflex

¹re·flex

noun \ˈrē-ˌfleks\

Definition of REFLEX

1

a : reflected heat, light, or color b : a mirrored image

2

a : an automatic and often inborn response to a stimulus that involves a nerve impulse passing inward from a receptor to the spinal cord and thence outward to an effector (as a muscle or gland) without reaching the level of consciousness and often without passing to the brain <the knee-jerk reflex> b : the process that culminates in a reflex and comprises reception, transmission, and reaction c reflexes pl : the power of acting or responding with adequate speed