1. Either of two spongy, saclike respiratory organs in air-breathing vertebrates, occupying the chest cavity together with the heart and functioning to provide oxygen to the blood while removing carbon dioxide.
2. A similar organ in some invertebrates, including spiders and terrestrial snails.
at the top of (one's) lungs
As loudly as one's voice will allow.
[Middle English lunge, from Old English lungen, lungs; see legwh- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.