Reaction may refer to a process or to a

response Response may refer to: *Call and response (music), musical structure *Reaction (disambiguation) *Request–response **Output or response, the result of telecommunications input *Response (liturgy), a line answering a versicle * Response (music) o ...

to an action, event, or exposure.

Physics and chemistry

Chemical reaction A chemical reaction is a process that leads to the chemistry, chemical transformation of one set of chemical substances to another. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an Gibbs free energy, ...

Nuclear reaction In nuclear physics and nuclear chemistry, a nuclear reaction is a process in which two atomic nucleus, nuclei, or a nucleus and an external subatomic particle, collide to produce one or more new nuclides. Thus, a nuclear reaction must cause a t ...

Reaction (physics) As described by the third of Newton's laws of motion of classical mechanics, all forces occur in pairs such that if one object exerts a force on another object, then the second object exerts an equal and opposite reaction force on the first. The t ...

, as defined by Newton's third law * Chain reaction (disambiguation)

Biology and medicine

Adverse drug reaction An adverse drug reaction (ADR) is a harmful, unintended result caused by taking medication. ADRs may occur following a single dose or prolonged administration of a drug or may result from the combination of two or more drugs. The meaning of this ...

Allergic reaction Allergies, also known as allergic diseases, are various conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include Allergic rhinitis, hay fever, Food allergy, food al ...

Reflex In biology, a reflex, or reflex action, is an involuntary, unplanned sequence or action and nearly instantaneous response to a stimulus. Reflexes are found with varying levels of complexity in organisms with a nervous system. A reflex occurs ...

, neural reaction *

Hypersensitivity Hypersensitivity (also called hypersensitivity reaction or intolerance) is an abnormal physiological condition in which there is an undesirable and adverse immune response to an antigen. It is an abnormality in the immune system that causes Imm ...

, immune reaction *

Intolerance (disambiguation) Intolerance may refer to: * Hypersensitivity or intolerance, undesirable reactions produced by the immune system * ''Intolerance'' (film), a 1916 film by D. W. Griffith * ''Intolerance'' (album), the first solo album from Grant Hart, formerly o ...

* Light reaction (disambiguation)

Psychology

Emotion Emotions are physical and mental states brought on by neurophysiology, neurophysiological changes, variously associated with thoughts, feelings, behavior, behavioral responses, and a degree of pleasure or suffering, displeasure. There is ...

al, reaction * Reactivity *

Proactivity Proactivity or proactive behavior refers to self-initiated behavior that endeavours to solve a problem before it has occurred. Proactive behavior involves acting in advance of a future situation, rather than reacting. It refers to taking control ...

, opposite of reactive behaviour *

Reactive attachment disorder Reactive attachment disorder (RAD) is described in clinical literature as a severe attachment disorder, disorder that can affect children, although these issues do occasionally persist into adulthood.DSM-IV-TR (2000) American Psychiatric Asso ...

Politics and culture

Reactionary In politics, a reactionary is a person who favors a return to a previous state of society which they believe possessed positive characteristics absent from contemporary.''The New Fontana Dictionary of Modern Thought'' Third Edition, (1999) p. 729. ...

, a political tendency *

Reaction video A reaction video, or a react video, is a video in which one or more persons react to something. Videos showing the emotional reactions, criticism or commentary of people viewing movies, television series episodes, film trailers, music videos, news, ...

Commentary (disambiguation) Commentary or commentaries may refer to: Publications * ''Commentary'' (magazine), a U.S. public affairs journal, founded in 1945 and formerly published by the American Jewish Committee * Caesar's Commentaries (disambiguation), a number of works ...

Proper names and titles

* ''Reaction'' (album), a 1986 album by American R&B singer Rebbie Jackson ** "Reaction" (song), the title song from the Rebbie Jackson album *"Reaction", a single by

Dead Letter Circus Dead Letter Circus were an Australian alternative rock band from Brisbane, Queensland. Their 2010 debut album '' This Is the Warning'' debuted at No. 2 on the Australian album charts and spawned a number of singles that were played heavily ...

*''Reactions'', a 2018 album by The Mods *

ReAction GUI ReAction GUI is the widget toolkit engine that is used in AmigaOS 3.2–4.1. It is an evolution of ClassAct, which is an object-oriented system of classes that enhanced the aspect of the Workbench 2.0 GUI of AmigaOS. History The native Amiga ...

, a GUI toolkit used on AmigaOS * Reaction.life, a political news and commentary website edited by Iain Martin *

Reaction Records Reaction Records was an independent British record label, run by music executive Robert Stigwood in 1966 and 1967. Although Reaction released only three albums, one EP and eighteen singles in its brief existence, its roster included two of th ...

, a record label *''

TNA Reaction ''TNA Reaction'' is an American professional wrestling-focused documentary-style television program by Total Nonstop Action Wrestling, Total Nonstop Action Wrestling (TNA) that aired in the United States and Canada on Paramount Network, Spike. Th ...

'', a former documentary show of TNA Wrestling (now known as Impact Wrestling) behind the scenes * Reaction (''The Spectacular Spider-Man''), an episode of the American animated television series ''The Spectacular Spider-Man'' *''The Reaction'', a novel in the ''Animorphs'' series * ''Reactions'' (journal), a chemistry journal published by MDPI

Physics and chemistry

Biology and medicine

Psychology

Politics and culture

Proper names and titles

See also