I also find it interesting that the aerospace/defense world (and co-influencing cultures in engineering and government) have sometimes used 'unk-unk' as shortha

I also find it interesting that the aerospace/defense world (and co-influencing cultures in engineering and government) have sometimes used 'unk-unk' as shorthand for 'unknown unknowns'. http://www.waywordradio.org/unk_unk/ http://www.waywordradio.org/unk_unk/