Gaslight is a term that has been used to refer to a variety of different things. The most common usage of the term is in reference to a type of lighting technology that was popular in the late 19th and early 20th centuries. The crossword solutions for the term Gaslight are ERA (3 letters) and JET (3 letters). ERA refers to the ERA in which gaslight was popular, while JET refers to the type of gas used in the lamps.