I'd humbly suggest that somewhere should be found a small amount of space to formally recognize that perplexity, to most English speakers' understanding, a state of confusion or bewilderment. I think it's great to learn details about this math theory, but perhaps someone can find a spot to mention the origin of the word or any kind of clue/reference to the actual non-math meaning of perplexity.
"Perplexity Per Word" is taken verbatim from the following uncited source:  --188.8.131.52 (talk) 05:32, 27 May 2010 (UTC)
It's just perplexity scaled by the number of words. It's a really common term and would be even more common if most papers didn't just say "perplexity" and assume the reader knows it's per word. --184.108.40.206 (talk) 17:44, 20 April 2011 (UTC)