The Spanish word 'pulmón' (meaning 'lung') comes from the Latin word 'pulmo', which had the same meaning. The Latin term itself can be traced back to Ancient Greek, where two variant forms existed: 'pleumon' and 'pneumon', both meaning 'lung'. The Greek forms show an interesting alternation between 'pl-' and 'pn-' sounds at the beginning of the word, with the 'pn-' variant ultimately influencing related medical terms we use today.

In Spanish, 'pulmonar' (pulmonary) and 'pulmonía' (pneumonia) are closely related words that derive from the same root as 'pulmón'. These medical terms maintain a clear connection to the basic meaning of 'lung' and are commonly used in medical contexts.

English speakers might recognize the connection to words like 'pneumonia', 'pneumatic', and 'pulmonary', which all trace back to the same Greek roots. While 'pneumonia' and 'pulmonary' maintain the connection to lungs and breathing, 'pneumatic' (relating to air or wind pressure) shows how the meaning expanded to include air-related concepts more broadly. The 'pn-' beginning in these English words comes from the Greek 'pneumon' variant, while the 'pulm-' beginning in 'pulmonary' comes through the Latin path, just like Spanish 'pulmón'.