alveolus
noun [ C ] anatomy specialized uk/ˌæl.viˈəʊ.ləs/ us/ælˈviː.ə.ləs/ alveoli uk/ˌæl.viˈəʊ.laɪ/ us/ælˈviː.ə.laɪ/
肺泡（肺中的细小气囊，细胞壁薄，有助于氧气进入血液）
one of the many very small air bags in the lungs, with thin walls that allow oxygen to enter the blood