Kingdom Prokaryotae is a biological classification system used to describe a group of organisms that lack a clearly defined nucleus and other membrane-bound organelles. However, due to recent advancements in scientific research, the term "Kingdom Prokaryotae" has become outdated, and synonyms such as "Bacteria" and "Archaea" are now commonly used. Bacteria and Archaea comprise the majority of microorganisms on Earth, and they play critical roles in various ecological systems. While Bacteria and Archaea share certain characteristics, such as their prokaryotic cell structure, each group has unique features that distinguish them from one another. By using these synonyms accurately, scientists can communicate more effectively and better understand the underlying biological processes at play in the natural world.