lung

The English word "lung" traces its origins to Old English "lungen," which was originally a plural form referring to the pair of respiratory organs.‍​‌​‌​‌​‌​‍​‍​‌​‌​‌​‍​‍​‌​‍​‌​‌​‍​‌​‌​‍​‍​‌​‌​‌​‌​‌​‍​‌​‍​‌​‍​‌ This term is attested before 900 CE and reflects a common Germanic root. The Old English "lungen" derives from the Proto-Germanic root *lungw-, a term that is generally reconstructed with the meaning "the light organ." This designation is closely associated with the physical property of the lungs being notably light compared to other internal organs, a characteristic that is emphasized by the fact that lungs are the only internal organs that float when placed in water.

The Proto-Germanic *lungw- itself is believed to stem from the Proto-Indo-European (PIE) root *lengʷh-, which carries the sense of "light in weight" or "not heavy." This PIE root is hypothetical but widely accepted among historical linguists as the source of various terms across Indo-European languages that relate to lightness or floating. The semantic motivation behind naming the lung after its lightness is thus rooted in the physical observation of the organ’s buoyancy, a feature that evidently held significance in early anatomical understanding.

This semantic pattern is not unique to the Germanic branch but appears to be a shared Indo-European conceptualization. For instance, the Latin word for lung, "pulmō," is thought to be connected to the Greek "πλευμών" (pleumōn), also meaning lung. Both Latin and Greek terms are etymologically linked to the Greek verb "πλέω" (pleō), meaning "to float" or "to sail." This connection suggests that the lungs were similarly named in these languages for their buoyant quality, reinforcing the idea that the lightness of the lungs was a salient feature recognized across different Indo-European-speaking cultures.

the Latin "pulmō" and Greek "pleumōn" are not inherited cognates of the Germanic *lungw- but rather represent a parallel semantic development within the broader Indo-European family. While all these terms share a conceptual root in the idea of lightness or floating, their phonological forms and specific derivations differ, reflecting separate linguistic evolutions within their respective branches.

The Old English "lungen" itself is a plural noun, which is somewhat unusual in modern English usage where "lung" is singular and "lungs" is plural. This plural form in Old English likely reflects the paired nature of the organs. Over time, the singular form "lung" emerged in Middle English, influenced by the general tendency in English to treat such paired body parts as countable singulars.

the English word "lung" descends from Old English "lungen," rooted in Proto-Germanic *lungw-, which in turn derives from the Proto-Indo-European root *lengʷh-, meaning "light in weight." This etymology is grounded in the physical characteristic of the lungs being the lightest internal organs, a trait that inspired similar naming conventions in other Indo-European languages such as Latin and Greek. Although the Latin and Greek terms are not direct cognates of the Germanic word, they share a common semantic field related to buoyancy and lightness, illustrating a widespread Indo-European conceptualization of the lungs based on their unique physical property.