Definition of gaslight

The term "gaslight" originally referred to the use of gas as a lighting source in buildings. In the mid-19th century, gas lamps were becoming increasingly popular as a replacement for traditional candle and oil lamps. These lamps burned a gas, typically coal or gasoline, and provided a brighter, more consistent light than the previous sources. The verb "gaslight" emerged in the late 19th century and was originally used to describe the act of changing the intensity of gas lighting in a room to create different ambiances or moods. It was sometimes used as a means of manipulating a person, such as dimming the lights during a romantic evening to enhance the mood. However, by the early 20th century, "gaslight" had taken on a new and more sinister meaning. In the play "Gas Light", written by Patrick Hamilton in 1938, "gaslighting" described a form of psychological abuse in which a person manipulates another through false information and denial of things that they know to be true. The term soon entered the Oxford English Dictionary, and by the 1940s, it had become a part of everyday English. Today, "gaslighting" is still used to describe a type of psychological manipulation, but the term has also come to be used more broadly to refer to any attempt to mislead or deceive someone by presenting false information as the truth.