Definition of acinus in English:



  • 1A small saclike cavity in a gland, surrounded by secretory cells.

    • ‘The airway wall is composed of many interrelated structural components such as epithelium, connective tissue, vessels, muscle, and mucus-secreting gland acini.’
    • ‘Small residual ducts and islands of intact salivary gland acini predominantly composed of serous-type glandular epithelium were present.’
    • ‘The mass also contained cystic spaces lined by columnar epithelium, sebaceous glands, cartilage, smooth muscle, and pancreatic acini.’
    • ‘The lesion displayed unremarkable pancreatic lobules with acini, ducts, and islets of Langerhans cells.’
    • ‘In cases with moderate or advanced changes, marked immunoreactivity was observed in the interlobular area and in the area surrounding both the acini and intralobular ducts.’
    bag, pouch, bladder, blister
    View synonyms
  • 2A region of the lung supplied with air from one of the terminal bronchioles.

    • ‘The acinus or primary pulmonary lobule (the basic unit of gas exchange) consists of one terminal bronchiole, two to five generations of respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.’
    • ‘A spectrum of airborne organic particulate matter, appropriately sized to reach pulmonary acini, produces this disease.’
    • ‘Primary bronchiolar disorders are separated from diseases primarily affecting more distal components of the pulmonary acinus and large airway diseases in which prominent secondary bronchiolar changes may be seen.’
    • ‘Panlobular emphysema, also referred to as panacinar emphysema, affects the acinus of the entire secondary lobule.’
    • ‘Emphysema is classified into three subtypes based on the portion of the acinus that is involved.’


Mid 18th century: Latin, literally a kernel.