Definition of alveolus in English:


Pronunciation /alˈvɪələs//ˌalvɪˈəʊləs/


  • 1Any of the many tiny air sacs of the lungs which allow for rapid gaseous exchange.

    • ‘Holes in the lungs occur as the alveoli air sacs break down.’
    • ‘As altitude increases above sea level, atmospheric pressure drops with a parallel decrease in the amount of oxygen available at the blood/air interface in the lung alveolus.’
    • ‘He found a major cause of bronchial asthma and many other chronic diseases to be a deficiency of carbon dioxide in the alveolus of our lungs.’
    • ‘Many alveoli in the functioning lung can remain at low volume for extended periods.’
    • ‘Scientists also suspect that air pollutants might dampen the growth of alveoli, tiny air sacs in the lungs.’
    1. 1.1 An acinus (saclike cavity) in a gland.
      • ‘Carbon dioxide in the lungs is 4.5 to 6%, in the blood of alveolus 6.5% and in cells 7%.’
  • 2The bony socket for the root of a tooth.

    • ‘These problems can be fixed by grafting bone matter onto the alveolus.’
    • ‘No preserved teeth or alveoli can be observed in the premaxilla and dentary bones.’
    • ‘The tooth row is present throughout the entire preserved length of the jaw and possesses 16 teeth and empty alveoli.’
    • ‘Only a few, fragmentary teeth are preserved, and judging by the fragments and the size of alveoli, the teeth were gracile.’
    • ‘The tooth is two-rooted, with each root housed in its own alveolus.’


Late 17th century: from Latin, ‘small cavity’, diminutive of alveus.