‘Behind us in the caves of the Deep are three parts of the folk of Westfold, old and young, children and women,’ said Gamling. ‘But great store of food, and many beasts and their fodder, have also been gathered there.’
JRR Tolkien, The Lord of the Rings, Volume 2: “The Two Towers”, Book Three, Chapter VII, “Helm’s Deep”
By three parts, Gamling means “three parts of four”, or “three quarters”. Or, at least, so I assume. Why do I assume that? It’s an assumption built in so deeply that I have no idea where it comes from. Is it a correct assumption? How long has the assumption that everything has four parts (or, rather, that a part means a quarter) been around? And is it still safe to use language that way today?