What is the origin of the term, 101?
Um, well, people needed a number higher than 100 but not quite as high as 102.
I’m afraid I’m unfamiliar with this number as a “term.” In what context have you heard it?
The only thing I can think of that you might mean is something like, “Hey, that’s Life 101.” If that’s the case, it refers to something very simple or basic. This comes, of course, from the tendency of colleges to offer very basic courses as a “100” level (Literature 101, Algebra 103), as opposed to advanced studies in the 200 or 300 level, for example.