CNS is a three-letter abbreviation with multiple meanings, as described below:
- Cell, Nature, and Science (CNS), an acronym used to describe the three most prestigious scientific journals involved in biomedical research.
- Central nervous system, consists of the brain and spinal cord.
- Clinical nurse specialist.
- "Coagulase-negative staphylococcus", a term to describe all staphylococcus species that are not staphylococcus aureus.
- Crigler-Najjar syndrome a rare hereditary disease