O Grão Caudilho

I was a briefly stumped by this. Grão means grain, normally, and caudilho looks familiar but looks like it ought to be something to do with a tail (cauda). It’s a set phrase though. Caudilho is actually descended from Spanish word meaning the chief, the head man, the dictator. So grão caudilho means… The grain chief? No, grão has a hidden secret meaning, if you scroll down a bit on its priberam page, it can be an adjective, where it’s just a form of “grande”. It’s the masculine form of Grã, as in Grã-Bretanha. So grão caudilho = the big boss, the big cheese.