infrakingdom
Infrakingdom is a taxonomic rank that has appeared in various biological classification schemes. It is used to designate a broad subdivision within a kingdom, intended to group together major lineages that are more inclusive than a subkingdom but more specific than the kingdom as a whole. The exact placement of the infrakingdom, when it is employed, varies by system; in some frameworks it lies between subkingdom and phylum, while in others it is considered a rank above subkingdom or treated as an optional or historical concept.
Historically, infrakingdoms were proposed to reflect large-scale evolutionary relationships within very diverse kingdoms such as animals,
In contemporary taxonomy, infrakingdoms are largely considered optional or historical rather than universally accepted, and many
Etymology and overview: the term combines infra- meaning below with kingdom, signaling a tier below the kingdom