Synonyms for Monarch (same or very similar meaning)
WordNet sense 1 (a nation's ruler or head of state usually by hereditary right):
sovereign, crowned headWordNet sense 2 (large migratory American butterfly having deep orange wings with black and white markings; the larvae feed on milkweed):
Danaus plexippus, milkweed butterfly, monarch butterflyFrom the ODE community, based on WordNetadd/edit