The word gaslighting (referring to the behavior described in the above amateur psychology section) is occasionally used in clinical literature, but is considered a colloquialism by the American Psychological Association. Gaslighting is distinct from genuine relationship conflict in that one party manipulates the perceptions of the other. Over time, the listening partner may exhibit symptoms often associated with anxiety disorders, depression, or low self-esteem. Gaslighting typically occurs over a long duration and not on a one-off basis.

one partner is consistently negating the other's perception, insisting that they are wrong, or telling them that their emotional reaction is irrational or dysfunctional.

one partner is consistently listening and considering the other partner's perspective.

Gaslighting is different from genuine relationship disagreement, which is both common and important in relationships. Gaslighting is typically effective only when there is an unequal power dynamic or when the gaslighted has shown respect to the gaslighter. Gaslighting involves two parties the 'gaslighter', who persistently puts forth a false narrative in order to manipulate, and the 'gaslighted', who struggles to maintain their individual autonomy. Gaslighting is a term used in self-help and amateur psychology to describe a dynamic that can occur in personal relationships (romantic or parental) and in workplace relationships. Oxford University Press named gaslighting as a runner-up in its list of the most popular new words of 2018.

The American Dialect Society named gaslight the 'most useful' new word of 2016. The term has received a number of notable recognitions. Merriam-Webster defines it as ' psychological manipulation' to make someone question their 'perception of reality' leading to 'dependence on the perpetrator'. Largely an obscure or esoteric term until gaining traction in the mid-2010s – The Times only used it nine additional times in the following 20 years – it has broadly seeped into the English lexicon since, and is now used more generally. According to the American Psychological Association in 2021, gaslighting 'once referred to manipulation so extreme as to induce mental illness or to justify commitment of the gaslighted person to a psychiatric institution'.

The gerund form gaslighting was first used in the 1950s, particularly in the episode of The Burns and Allen Show in The New York Times, it was first used in a 1995 column by Maureen Dowd. The term 'gaslighting' itself is neither in the screenplay nor mentioned in either the films or the play in any context. In the story the husband secretly dims and brightens the indoor gas-powered lighting but insists his wife is imagining it, making her think she is going insane. Set among London's elite during the Victorian era, it portrays a seemingly genteel husband using lies and manipulation to isolate his heiress wife and persuade her that she is mentally unwell so that he can steal from her. The film was then remade in 1944 in America – also as Gaslight – and it is this film which has since become the primary reference point for the term. The origin of the term is the 1938 British thriller play Gas Light by Patrick Hamilton, which provided the source material for the 1940 British film, Gaslight. Etymology Charles Boyer, Ingrid Bergman, and Joseph Cotten in the film Gaslight (1944) In a 2022 Washington Post report, it was described as a 'trendy buzzword' frequently used to describe ordinary disagreements, rather than those situations that align with the word's historical definition. This term, derived from the 1944 American film Gaslight, entered colloquial English usage in the mid-2010s. Merriam Webster cites deception of one's memory, perception of reality, or mental stability. In contemporary language, gaslighting is a colloquialism describing the subjective experience of having one’s reality repeatedly questioned by another. Gaslighting historically referred to extreme psychological manipulation to commit an individual to a psychiatric institution or cause mental illness with the intent to brainwash. For illumination derived from burning gas, see Gas lighting.

Gaslight 1940