Homonym: Gas Light (Gaslighting)
"Gas Light" is a psychological thriller play written by Patrick Hamilton in 1938. The story revolves around a married couple, Gregory and Bella, living in Victorian London. Gregory manipulates Bella into doubting her own perceptions and sanity, primarily by dimming the gas lights and denying it when she notices.
The term "gaslighting" has since emerged from this play, referring to a form of emotional abuse where one person makes another question their reality. The play has been adapted into several films, most notably the 1944 version starring Ingrid Bergman and Charles Boyer, which further popularized the concept.