noun re·flex \ˈrē-ˌfleks\

: an action or movement of the body that happens automatically as a reaction to something

: something that you do without thinking as a reaction to something

reflexes : the natural ability to react quickly

Full Definition of REFLEX

a archaic :  reflected heat, light, or color
b :  a mirrored image
c :  a copy exact in essential or peculiar features
a :  an automatic and often inborn response to a stimulus that involves a nerve impulse passing inward from a receptor to a nerve center and thence outward to an effector (as a muscle or gland) without reaching the level of consciousness — compare habit 7
b :  the process that culminates in a reflex and comprises reception, transmission, and reaction —called also reflex action
c plural :  the power of acting or responding with adequate speed
d :  a way of thinking or behaving
:  a linguistic element (as a word or sound) or system (as writing) that is derived from a prior and especially an older element or system <boat is the reflex of Old English bāt>

Examples of REFLEX

  1. reflexes such as swallowing and blinking
  2. Disagreeing with my suggestions has become almost a reflex for him.
  3. an athlete with great reflexes
  4. My reflexes are slower now that I'm older.

Origin of REFLEX

Latin reflexus, past participle of reflectere to reflect
First Known Use: 1508



Definition of REFLEX

:  directed back on the mind or its operations :  introspective
:  reflexed
:  produced or carried out in reaction, resistance, or return
of an angle :  being between 180° and 360°
:  of, relating to, or produced by a reflex without intervention of consciousness
re·flex·ly adverb

Origin of REFLEX

Latin reflexus
First Known Use: 1649
REFLEXLY Defined for Kids


noun re·flex \ˈrē-ˌfleks\

Definition of REFLEX for Kids

:  an action or movement that is made automatically without thinking as a reaction to a stimulus
re·flex·es plural :  the natural ability to react quickly <A driver needs good reflexes.>


Next Word in the Dictionary: reflex arcPrevious Word in the Dictionary: refletAll Words Near: reflex
How to use a word that (literally) drives some people nuts.
Test your vocab with our fun, fast game
Ailurophobia, and 9 other unusual fears