waterproof outercoat or raincoat, named after a Scottish chemist, Charles Macintosh (Macintosh, Charles) (1766–1843), who invented the waterproof material that bears his name. The fabric used for a mackintosh was made waterproof by cementing two thicknesses of it together with rubber dissolved in a coal-tar naphtha solution.

Macintosh patented his fabric in 1823. The word mackintosh has become a general term for any raincoat.