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reflex
/ˈrɛflɛks/
an automatic, involuntary response to a stimulus
When the doctor tapped her knee, her leg jerked in a reflex.
The knee-jerk reaction was an involuntary reflex triggered by the tap.
formal
an automatic, involuntary response to a stimulus, such as a muscle contraction or movement, triggered by a sensory input
The sudden loud noise caused a reflexive jump.
The person reacted instinctively to the loud noise.
Reflexes are typically mediated by the spinal cord and do not involve conscious thought.
informal
a quick, instinctive reaction or response
She had a reflex to duck when she heard the crash.
She instinctively reacted by ducking at the sound of the crash.
In informal usage, 'reflex' can describe any quick, automatic reaction, not just physiological responses.
Collocations
reflex actionan automatic physical responsereflex responsean involuntary reaction to a stimulus
Related Phrases
Pro Tip
Medical vs. Informal Usage
In medical contexts, 'reflex' refers strictly to involuntary physiological responses. In everyday language, it can describe any quick, instinctive reaction.
Gold Rule
Reflex vs. Reaction
A reflex is an involuntary, automatic response, while a reaction can be conscious or unconscious.
Word Origin
From Latin 'reflexus', meaning 'bent back' or 'reflected', referring to the idea of a response being reflected back to the stimulus.
Usage Notes
In medical contexts, 'reflex' refers specifically to involuntary physiological responses. In everyday language, it can describe any quick, instinctive reaction.
Word Breakdown
re-
back
prefix-flex
bend
rootEnglish Dictionary