In Biology and Botany, a domain (also superregnum, superkingdom, or empire) is a top level in the system of taxonomy, which is a form of classification, using Subsumptive Relations. It is striking that there is no universal agreement with at least 3 contending models: a) 2 Empire System top-level groupings of Prokaryota (or Monera) and Eukaryota empires. 2) 5 Kingdom system with top-level groupings of Protista, Monera, Fungi, Plantae, and Animalia. 3) 3 Domain system of Carl Woese (1990), with top-level groupings of Archaea, Eubacteria, and Eukaryota domains.