Organisms are classified into three Domains and six Kingdoms. The three Domains are Bacteria, Archaea, and Eukarya. The six kingdoms are Archaebacteria, Eubacteria, Fungi, Protista, Plantae, and Animalia. Members of Kingdom Archaeabacteria are in the Domain Archaea. Members of the Kingdom Eubacteria are in the Domain Bacteria, and members of the Kingdoms Fungi, Protista, Plantae, and Animalia are all in the Domain Eukarya.
When I first started teaching high school biology a number of years ago, all bacteria were classified in the Kingdom Monera. Scientists have since transition from five Kingdoms to six Kingdoms. The Six-Kingdom System of Classification makes more sense due to the significant differences between archaebacteria and eubacteria. The Kingdom Monera was too broad of a classification.