The term "arch-duchesses" refers to the female rulers of certain Austrian territories. Some synonyms for this word can be "princesses," "duchesses," "empresses," "queens," and "rulers." These words all denote women who hold power and authority over a region or a country. They are often associated with leadership, sovereignty, and command. The term "arch-duchesses" has a specific historical and cultural context, but these synonyms can be used more broadly to describe women who govern or hold high positions of authority. Each word has its own connotations and nuances, but together they paint a picture of women who are respected and admired for their intelligence, strength, and leadership abilities.