The Irish language in everyday usage. - Mac is the Irish language word for son sometimes abbreviated to Mc in surnames. McIntosh is a transliteration of ‘Mac an Taoiseach’ which in turn translates as son of the chieftain. Nowadays however i t would translate as son of the prime minister for ‘Taoiseach’ is the title given to the Irish Prime Minster. The source of the McIntosh surname is from the Gaelic regions of Scotland.
Jef Raskin employed by Apple computers envisioned an easy-to-use, low-cost computer for the average consumer and he wanted to name the computer after his favourite type of apple, the McIntosh. However, the name had to be changed for legal reasons for it was too similar to the ‘McIntosh audio equipment’ brand. Hence the Macintosh brand name but mostly marketed as the Mac.