Genus Diplococcus is a type of bacteria that is spherical and occurs in pairs. There are several synonyms for this genus, such as Streptococcus, which is often referred to as the "chain-forming Diplococcus" due to its similarity in shape and structure. Other related genera include Neisseria, which share some common morphological characteristics but differ in other clinical and biochemical properties. The genus Diplococcus is historically significant as the first bacterium discovered causing pneumonia, and many strains have been isolated from clinical specimens. Understanding the synonyms and related genera of Diplococcus is important for medical professionals and researchers alike in the fight against infectious diseases caused by this type of bacteria.