Here's a breakdown:
* מַלְכוּ (Malḵū) is the root word for "king"
* -תָא (-ṯā) is the suffix that indicates a state or condition, similar to the English "-ship" or "-dom".
So, מַלְכוּתָא translates literally to "kingship" or "the state of being king."
In some contexts, מַלְכוּתָא can also be translated as "rule," "dominion," or "sovereignty."