It’s a popular word in undergraduate English departments. My friend in college told me his professor (jokingly) threatened to hand an “F” out to any paper that talked about the liminality of the text because of the sheer number of them he got every semester.

I encountered this word for the first time a couple of months ago and have been seeing it everywhere since.

For anyone in New York, there’s a pretty good art exhibit in Brooklyn about liminality called the Museum of Future Experience. (The museum might do other exhibits, but it’s been liminality for as long as I’ve known it).

This is the Baader–Meinhof phenomenon: https://en.wikipedia.org/wiki/Frequency_illusion