mother of all

Calque of Arabic أُمّ الـ‎ (ʾumm al--); popularized after its use by Saddam Hussein, then president of Iraq, in reference to the Gulf War as أُمّ المَعَارِك‎ (ʾumm al-maʿārik, “mother of battles”).

mother of all —

1. (colloquial) Used before a plural noun to form a compound noun having the sense of: the greatest or largest of its kind.
   • 2003, "2003 Movie Guide", Christian Science Monitor, 26 Dec 03:

     Driving to a dinner engagement, a Parisian woman gets stuck in the mother of all traffic jams, offers a ride to a handsome pedestrian, and enters a fleeting affair that catches both of them by surprise.

   • 2006, Jean Chatzky, "Get the Scoop", Money, vol. 35.8:

     Five mail-order ice creams. Four pregnant women. Welcome to the mother of all taste tests.

• mother
• Appendix:American Dialect Society words of the year