the.com/grand duke

A monarch's rank for countries too small to call it an empire but too proud to call it a province.

means A sovereign ruler of a grand duchy, outranking a mere duke but sitting a notch below a king or emperor — also used as a title for certain royal princes who aren't actually heads of state.

from From 'grand' (Latin grandis, 'big, full-grown') plus 'duke' (Latin dux, 'leader,' the word Rome used for military commanders who ran provinces). Stack 'grand' on top of 'duke' and you get a title medieval and early-modern Europe used to dress up rulers of places like Luxembourg, Tuscany, or Lithuania — states too substantial to be a mere duchy but not quite kingdom material. It let a ruler outrank the neighboring dukes without provoking the actual kings.

current examples
Luxembourg is the last one standing
russian version
tsar's sons, dozens of them, all titled
rank order
outranks duke, undercuts king
etymology
literally means great great in some lines
the.com · every word