Diplococcus pneumoniae is a bacterium that causes a wide range of infections, including pneumonia, meningitis, and sepsis. It is often referred to as Streptococcus pneumoniae, pneumococcus, or simply, S. pneumoniae. Other synonyms for Diplococcus pneumoniae include pneumokokkus, Diplococcus lanceolatus, and Diplococcus pneumonia. This bacterium is many times misidentified as Staphylococcus aureus or Haemophilus influenzae in clinical settings. Regardless of what it is called, Diplococcus pneumoniae infections can be severe, especially in high-risk populations such as children, older adults, and those with weakened immune systems. Proper identification of the bacterium is critical for accurate diagnosis and treatment.