Educational Content: This article is for informational purposes only and does not constitute medical advice. Always consult a healthcare provider for diagnosis and treatment.
Definition of Pulmonary acinus
Medically reviewed by Min Clinic Staff | Updated: January 2026
Pulmonary acinus: The ending of a tiny airway in the lung, where the alveoli (air sacs) are located.
In anatomy, an acinus is a round cluster of cells, usually epithelial cells, that looks somewhat like a knobby berry.
The word "acinus" means "berry" in Latin. (The plural is "acini".) There are also acini, round clusters of epithelial cells, in the salivary glands and in the pancreas.