From a programming perspective it is a way go generalize adding two things together, but where the order might matter (or might not!). + is a monoid. It adds t

From a programming perspective it is a way go generalize adding two things together, but where the order might matter (or might not!). + is a monoid. It adds to numbers together. (3+3)+4 = 3+(3+4) But also concatenation is a monoid "a" + ("b" + "c") = ("a" + "b") + "c". Monoids have an empty thing you can add to anything. E.g. 0 for + and "" for concatenation. In Haskell, Monoids are abstracted out into a typeclass so that you can write code on any monoid. For example fold up a list of monoid elements into a single element.