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

Stretching When the stress response is activated, your muscles tense up as a reflex to protect against pain or injury. —Noma Nazish, Forbes, 4 Nov. 2024

Doctors seemed to be trying everything, his family members said, but the news had been crushing: brain damage, lack of reflexes, emptiness in his eyes. —Jen Christensen, CNN, 28 Oct. 2024

Adjective

For one thing, markets had not significantly anticipated a Trump win in 2016, and indeed there was a reflex selloff on election night, which quickly reversed. —Michael Santoli, CNBC, 26 Oct. 2024

Based on the title character from the Netflix show Vida the Vet, this kit contains five sensory toys for treating patients, including a stethoscope with sound effects and reflex hammer. —Pamela Brill, Parents, 24 Oct. 2024

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