gaslight

noun

1. (countable, historical, uncountable)A lamp which operates by burning piped illuminating gas (or town gas).

   “He was renovated and refreshed, his soul was strengthened, and his countenance waxed cheerful, and he began to feel like himself again, under the brown canopy of metropolitan smoke, and among the cabs and gaslights.”

   “Open the windows once in awhile^([sic]) and give the air a chance to circulate in and out. In the evening, do not forget that the lamps and gaslights are using up a goodly supply of oxygen also—so freshen things up a little, once in awhile.”

2. (historical, uncountable)The light produced by the burning gas in such a lamp.

   “A year since I strained my eyes very severely, and have never dared to use them much since by gaslight.”

   “Then as the darkness descended, they began to shine with the mellow radiance of gaslight.”

verb

1. (formal, historical, transitive)To manipulate someone such that they doubt their own memory, perceptions of reality, or sanity, typically for malevolent reasons.

   “Sylvia is a beautiful woman whose business-partner husband is "gaslighting" her. (That means he's trying to drive her crazy.)”

   “[The men of McHale's Navy] decide to "gaslight" the already befuddled captain, to convince him he is going insane.”

   “"You're gaslighting me, for chrissakes."”

   “1967, Stan Freberg (comedian), on his "most excruciating experience with a producer" as interviewed in Humphrey, Hal. "'Dramatic' Role Played By Freberg." The Oregonian [Portland, OR]. February 11, 1967: II 3 col 3. I came home before he could gaslight me like Boyer did Bergman in the movie.”

   “Just in the nick of time Rachel finds out the truth about her life from Martha. … This is how I wanted to show the gaslighting that had been going on Rachel's entire life.”

2. (broadly, historical, informal, proscribed, transitive)To deceive, trick, or lie to.