mackintosh: [19] The rubberized material from which this waterproof coat was originally made was invented in the early 1820s by the British chemist Charles Macintosh (1766–1843). His name (misspelled with a k) is first recorded as being applied to the coat in 1836. The abbreviated form mac (or occasionally mack) dates from around the turn of the 20th century. [mackintosh etymology, mackintosh origin, 英语词源]
waterproof outer coat, 1836, named for Charles Macintosh (1766-1843), inventor of a waterproofing process (patent #4804, June 17, 1823). The surname is from Gaelic Mac an toisich "Son of the chieftain."