IPA: /ˈrɛɡ.nənt/
KK: /ˈrɛɡnənt/
Having the power to rule or govern, especially in the context of a monarch who reigns in their own right, such as a queen.
The queen regnant made important decisions for the kingdom.
Regnant → It is formed from "regnare" (meaning to reign) and the suffix "-ant" (indicating an agent or one who performs an action). The word "regnant" means one who reigns or is in a position of authority.
Think of someone who is 'reigning' ('regnare') — that's why regnant refers to someone who is in a position of power.