1. original meaning: source, origin, beginning
2. (following the
2010 movie): an infinite loop; a
thing that contains itself; a repetition of the same
thing, something with multiple layers; infinite regress, a vicious circle; a dream within a dream.
(referring to the concept of dreams inside other dreams, both up and down, and the famous line "we need to go deeper" from the movie.)
Essentially the same as the word "recursion", a word that a lot fewer young people know.