It means "the ability to sit through or endure something boring" AND "the ability to endure or persist in a task." As in:
I had great Sitzfleisch last night watching the Oscar Ceremony.
Sitzfleisch will be required this afternoon when I pick up my sons from school and let them know all electronic gadgets, including Wii, iPod Touch, iPad and PlayStation are off-limits until further notice.
There's a new sheriff in town, as they say.
|Policewoman, suffragette, 1908|