reflex

1 of 2

noun

re·​flex ˈrē-ˌfleks 

1

a

archaic : reflected heat, light, or color

b

: a mirrored image

c

: a copy exact in essential or peculiar features

2

a

: an automatic and often inborn response to a stimulus that typically involves a nerve impulse passing inward from a receptor to the spinal cord and then passing outward from the spinal cord to an effector (such 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

called also reflex action

c

reflexes plural : the power of acting or responding with adequate speed

d

: a way of thinking or behaving

3

: a linguistic element (such as a word or sound) or system (such as writing) that is derived from a prior and especially an older element or system

boat is the reflex of Old English bāt

reflex

2 of 2

adjective

1

: directed back on the mind or its operations : introspective

2

: reflexed

3

: produced or carried out in reaction, resistance, or return

4

of an angle : being between 180° and 360°

5

: of, relating to, or produced by a reflex without intervention of consciousness

reflexly adverb

Examples of reflex in a Sentence

Noun

reflexes such as swallowing and blinking

Disagreeing with my suggestions has become almost a reflex for him.

an athlete with great reflexes

My reflexes are slower now that I'm older.

Recent Examples on the Web

Noun

While the sun is partially obscured, some wavelengths that trigger pain are blocked, dulling the reflex to look away. —Daniel Wu, Washington Post, 9 Apr. 2024

Hunt had Northern make fists with both hands, then checked his grip strength and reflexes. —Ciara McCarthy, Fort Worth Star-Telegram, 2 Feb. 2024

Learning to fly an FPV well takes talent, good reflexes and plenty of practice. —David Hambling, Forbes, 20 Feb. 2024

From lipomas and cysts to keloids and tumors, Lee tackles them all with professionalism and a seemingly imperturbable gag reflex. —Briana Richert, James Mercadante, EW.com, 19 Feb. 2024

With athletic reflexes and reliable hands that would make NFL quarterbacks jealous, Gordon’s receiving skills have become an underrated cornerstone of the Denver Nuggets’ offense, often turning dangerous risks into thrilling highlights. —Bennett Durando, The Denver Post, 3 Feb. 2024

Coughing is a bodily reflex that offers protection from germs or irritants. —Claire Gillespie, Health, 17 Mar. 2024

Authoritarian reflexes returned to the political system, which began to control more and more aspects of social life. —Andrei Kolesnikov, Foreign Affairs, 7 Mar. 2024

Vestibular test battery: A test that checks the reflex of your inner ear balance system and eye muscles. —USA TODAY, 30 Jan. 2024

Adjective

By Kate Lindsay These days, turning on my Amazon Fire smart TV is like a reflex test. —Kate Lindsay, The Atlantic, 27 Feb. 2024

The Apgar Score, performed one minute and five minutes after a baby is born, called for a consistent, rapid evaluation of five categories associated with a newborn’s health: heart rate, respiration, muscle tone or activity, reflex response to stimulation, and skin color. —Amos Grünebaum, STAT, 23 Jan. 2024

The reflex explanation suggests that tickle simply requires an element of unpredictability or uncontrollability and is more like a reflex or some other stereotyped motor pattern. —Discover Magazine, 12 Apr. 2010

Following the alleged murder, far-right figures immediately began boosting conspiracies about the beheading being a false flag in favor of the Democrats—something that has virtually become a reflex action among far-right figures following major news. —David Gilbert, WIRED, 1 Feb. 2024

Related: Jarren Duran’s reflex reaction to injury ending what was fast becoming a successful season? —Julian McWilliams, BostonGlobe.com, 8 Sep. 2023

Other times, the orcas force the sharks upside down, and a reflex triggers the fish into a paralysis-like state. —Victoria Sayo Turner, Smithsonian Magazine, 12 July 2023

During that time, the other biologists woke her up, asked her questions and carried out reflex tests with her hands. —Smithsonian Magazine, 10 July 2023

The rear reflex reflectors may detach. —Detroit Free Press, 29 Aug. 2020

Word History

Etymology

Noun

Latin reflexus, past participle of reflectere to reflect

Adjective

Latin reflexus

First Known Use

Noun

1508, in the meaning defined at sense 1a

Adjective

1607, in the meaning defined at sense 1

Phrases Containing reflex

• Babinski reflex
• Babinski's reflex
• reflex arc
• reflex sympathetic dystrophy
• single-lens reflex

Kids Definition

reflex

1 of 2 noun

re·​flex ˈrē-ˌfleks 

1

: an automatic response to a stimulus in which a nerve message passes from a sense organ to the spinal cord and then to a point of action (as a muscle or gland) often without first passing to the brain

the knee-jerk reflex

compare habit sense 3

2

plural : the power of acting or responding with enough speed

an athlete with great reflexes

reflex

2 of 2 adjective

1

: produced in reaction, resistance, or return

2

: of, relating to, or produced by a reflex of the nervous system

reflex action

reflexly adverb

Medical Definition

reflex

1 of 2 noun

re·​flex ˈrē-ˌfleks 

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 plural : the power of acting or responding with adequate speed

reflex

2 of 2 adjective

1

: bent, turned, or directed back : reflected

2

: of, relating to, or produced by a reflex without intervention of consciousness