I was looking for an introduction to Semigroups and found an Introduction to Semigroups and Monoids by Pete L. Clark. The abstract says:
I know many working mathematicians who let loose a smirk or giggle when they hear the word “monoid”. What’s so funny?
I learnt many useful things reading the paper but didn't see this question resolved. Perhaps the author intended to answer it in a later section (the paper is incomplete).
So, why might a working mathematician smirk when they hear the word "monoid"?