Noun

• S: (n) chemical reaction, reaction ((chemistry) a process in which one or more substances are changed into others) "there was a chemical reaction of the lime with the ground water"
• S: (n) reaction (an idea evoked by some experience) "his reaction to the news was to start planning what to do"
• S: (n) reaction, response (a bodily process occurring due to the effect of some antecedent stimulus or agent) "a bad reaction to the medicine"; "his responses have slowed with age"
• direct hyponym / full hyponym
• S: (n) automatism (any reaction that occurs automatically without conscious thought or reflection (especially the undirected behavior seen in psychomotor epilepsy))
• S: (n) rebound (a reaction to a crisis or setback or frustration) "he is still on the rebound from his wife's death"
• S: (n) overreaction (an excessive reaction; a reaction with inappropriate emotional behavior)
• S: (n) galvanic skin response, GSR, psychogalvanic response, electrodermal response, electrical skin response, Fere phenomenon, Tarchanoff phenomenon (a change in the electrical properties of the skin in response to stress or anxiety; can be measured either by recording the electrical resistance of the skin or by recording weak currents generated by the body)
• S: (n) immune response, immune reaction, immunologic response (a bodily defense reaction that recognizes an invading substance (an antigen: such as a virus or fungus or bacteria or transplanted organ) and produces antibodies specific against that antigen)
• S: (n) anamnestic response, anamnestic reaction (renewed rapid production of an antibody on the second (or subsequent) encounter with the same antigen)
• S: (n) humoral immune response (an immune response (chiefly against bacterial invasion) that is mediated by B cells)
• S: (n) cell-mediated immune response (an immune response (chiefly against viral or fungal invasions or transplanted tissue) that involves T cells)
• S: (n) complement fixation (an immune response in which an antigen-antibody combination inactivates a complement (so it is unavailable to participate in a second antigen-antibody combination))
• S: (n) tropism (an involuntary orienting response; positive or negative reaction to a stimulus source)
• S: (n) ergotropism (an affinity for work)
• S: (n) geotropism (an orienting response to gravity)
• S: (n) heliotropism (an orienting response to the sun)
• S: (n) meteortropism (an effect of climate on biological processes (as the effect on joint pains etc.))
• S: (n) neurotropism (an affinity for neural tissues)
• S: (n) phototropism (an orienting response to light)
• S: (n) trophotropism (an orienting response to food)
• S: (n) thermotropism (an orienting response to warmth)
• S: (n) taxis (a locomotor response toward or away from an external stimulus by a motile (and usually simple) organism)
• S: (n) chemotaxis (movement by a cell or organism in reaction to a chemical stimulus)
• S: (n) negative chemotaxis (movement away from a chemical stimulus)
• S: (n) positive chemotaxis (movement toward a chemical stimulus)
• S: (n) kinesis (a movement that is a response to a stimulus but is not oriented with respect to the source of stimulation)
• S: (n) double take (a delayed reaction indicating surprise)
• S: (n) reflex, reflex response, reflex action, instinctive reflex, innate reflex, inborn reflex, unconditioned reflex, physiological reaction (an automatic instinctive unlearned reaction to a stimulus)
• S: (n) accommodation reflex (reflex changes in the eyes that enable an object to be focused on the retina)
• S: (n) Babinski, Babinski reflex, Babinski sign (extension upward of the toes when the sole of the foot is stroked firmly on the outer side from the heel to the front; normal in infants under the age of two years but a sign of brain or spinal cord injury in older persons)
• S: (n) belch, belching, burp, burping, eructation (a reflex that expels gas noisily from the stomach through the mouth)
• S: (n) blink, eye blink, blinking, wink, winking, nictitation, nictation (a reflex that closes and opens the eyes rapidly)
• S: (n) palpebration (repeated blinking or winking (especially if uncontrolled and persistent))
• S: (n) blush, flush (sudden reddening of the face (as from embarrassment or guilt or shame or modesty))
• S: (n) vomit, vomiting, emesis, regurgitation, disgorgement, puking (the reflex act of ejecting the contents of the stomach through the mouth)
• S: (n) rumination (regurgitation of small amounts of food; seen in some infants after feeding)
• S: (n) hematemesis, haematemesis (vomiting blood)
• S: (n) hyperemesis (severe and excessive vomiting)
• S: (n) hyperemesis gravidarum (hyperemesis during pregnancy; if severe it can result in damage to the brain and liver and kidney)
• S: (n) defecation reflex, rectal reflex (normal response to the presence of feces in the rectum)
• S: (n) yawn, yawning, oscitance, oscitancy (an involuntary intake of breath through a wide open mouth; usually triggered by fatigue or boredom) "he could not suppress a yawn"; "the yawning in the audience told him it was time to stop"; "he apologized for his oscitancy"
• S: (n) pandiculation (yawning and stretching (as when first waking up))
• S: (n) electric shock, electrical shock, shock (a reflex response to the passage of electric current through the body) "subjects received a small electric shock when they made the wrong response"; "electricians get accustomed to occasional shocks"
• S: (n) fart, farting, flatus, wind, breaking wind (a reflex that expels intestinal gas through the anus)
• S: (n) gulp, gulping (a spasmodic reflex of the throat made as if in swallowing)
• S: (n) knee jerk, knee-jerk reflex, patellar reflex (a reflex extension of the leg resulting from a sharp tap on the patellar tendon)
• S: (n) light reflex, pupillary reflex, miosis, myosis (reflex contraction of the sphincter muscle of the iris in response to a bright light (or certain drugs) causing the pupil to become smaller)
• S: (n) mydriasis (reflex pupillary dilation as a muscle pulls the iris outward; occurs in response to a decrease in light or certain drugs)
• S: (n) micturition reflex (relaxation of the urethral sphincter in response to increased pressure in the bladder)
• S: (n) pharyngeal reflex, gag reflex (normal reflex consisting of retching; may be produced by touching the soft palate in the back of the mouth)
• S: (n) pilomotor reflex, gooseflesh, goose bump, goosebump, goose pimple, goose skin, horripilation (reflex erection of hairs of the skin in response to cold or emotional stress or skin irritation)
• S: (n) plantar reflex (flexion of the toes when the sole of the foot is stroked firmly on the outer side from the heel to the front in persons over the age of 2 years; under 2 years the results should be extension of the toes (Babinski reflex))
• S: (n) rooting reflex (reflex consisting of head-turning and sucking movements elicited in a normal infant by gently stroking the side of the mouth or cheek)
• S: (n) startle, jump, start (a sudden involuntary movement) "he awoke with a start"
• S: (n) startle response, startle reaction (a complicated involuntary reaction to a sudden unexpected stimulus (especially a loud noise); involves flexion of most skeletal muscles and a variety of visceral reactions)
• S: (n) startle reflex, Moro reflex (a normal reflex of young infants; a sudden loud noise causes the child to stretch out the arms and flex the legs)
• S: (n) wince, flinch (a reflex response to sudden pain)
• S: (n) stretch reflex, myotactic reflex (reflex contraction of a muscle when an attached tendon is pulled; important in maintaining erect posture)
• S: (n) suckling reflex (reflex behavior in newborn mammals; includes finding and grasping the nipple in the mouth and sucking on it and swallowing the milk)
• S: (n) tremble, shiver, shake (a reflex motion caused by cold or fear or excitement)
• S: (n) sneeze, sneezing, sternutation (a symptom consisting of the involuntary expulsion of air from the nose)
• S: (n) hiccup, hiccough, singultus ((usually plural) the state of having reflex spasms of the diaphragm accompanied by a rapid closure of the glottis producing an audible sound; sometimes a symptom of indigestion) "how do you cure the hiccups?"
• S: (n) learned reaction, learned response (a reaction that has been acquired by learning)
• S: (n) conditional reflex, conditioned reflex, acquired reflex, conditional reaction, conditioned reaction, conditional response, conditioned response (an acquired response that is under the control of (conditional on the occurrence of) a stimulus)
• S: (n) conditioned avoidance, conditioned avoidance response (a conditioned response that anticipates the occurrence of an aversive stimulus)
• S: (n) passage, passing (a bodily reaction of changing from one place or stage to another) "the passage of air from the lungs"; "the passing of flatus"
• S: (n) answer (a nonverbal reaction) "his answer to any problem was to get drunk"; "their answer was to sue me"
• S: (n) transfusion reaction (reaction of the body to a transfusion of blood that is not compatible with its own blood; an adverse reaction can range from fever and hives to renal failure and shock and death)
• direct hypernym / inherited hypernym / sister term
• derivationally related form
• W: (v) react [Related to: reaction] (show a response or a reaction to something)
• S: (n) reaction ((mechanics) the equal and opposite force that is produced when any force is applied to a body) "every action has an equal and opposite reaction"
• domain category
• direct hypernym / inherited hypernym / sister term
• S: (n) reaction (a response that reveals a person's feelings or attitude) "he was pleased by the audience's reaction to his performance"; "John feared his mother's reaction when she saw the broken lamp"
• S: (n) reaction (extreme conservatism in political or social matters) "the forces of reaction carried the election"
• direct hypernym / inherited hypernym / sister term
• derivationally related form
• S: (n) reaction (doing something in opposition to another way of doing it that you don't like) "his style of painting was a reaction against cubism"