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
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
Bennett Durando, The Denver Post, 11 Nov. 2024
Emi is perfectly positioned with great reflexes again.
—Jacob Tanswell, The Athletic, 22 Aug. 2024
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
See all Example Sentences for reflex 
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Noun
When games are close, Malone’s reflex is to turn around, scan his bench and direct Jokic to the scorer’s table.
—Bennett Durando, The Denver Post, 11 Nov. 2024
Emi is perfectly positioned with great reflexes again.
—Jacob Tanswell, The Athletic, 22 Aug. 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
See all Example Sentences for reflex
Dictionary Entries Near reflex
Cite this Entry
“Reflex.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/reflex. Accessed 28 Nov. 2024.
Copy CitationKids 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 adjective1
: 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 adjective1
: bent, turned, or directed back : reflected
2
: of, relating to, or produced by a reflex without intervention of consciousness
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