Re:How the Colosseum was built and why it was an architectur...
by adrian_b on Saturday July 16, 2022 @03:36PM
(#32121203)
I believe that Knuth knew very well the true meanings of "concrete" and "discrete" and he has just made a word play exploiting the fact that the "-crete" suffixes in the 2 words are homonyms.
However, not all his readers have understood the pun.
If I were you, I would send an email to Knuth reporting the error. You may receive a reward check from Knuth himself, which will give you eternal bragging rights.