Largest subdivision of a lobe of the lung with its air supply from a major branch of the bronchus and having its own arterial blood supply.
Source:
PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 731 (https://doi.org/10.1515/pac-2015-1202)