Old-fashioned illumination is a term used to describe the use of gaslight, which is an 8-letter word. Gaslight was a popular form of lighting in the 19th century, and it involved the burning of flammable gas such as coal gas or natural gas. This type of lighting was used in homes, businesses, and public spaces, and it provided a soft, warm light. Gaslight was eventually replaced by electric lighting in the early 20th century.