In the 70’s, it was fashionable for intellectuals to abuse the term “grammar” to refer to any underlying principles. In one of his essays, Italo Calvino used the term “the grammar of tree” to refer to…. essentially developmental plant biology. I thought that was pretentious. But heh, in R programming, people are talking about the grammar of graphics and grammar of data manipulation again. It’s fashionable to call functions “verbs” again. Hello, structuralism! (PS: A philosopher friend informed me that this abuse of the word grammar started with Wittgenstein)