I was curious about the term, too. I found this [1], although it focused on asthma. I found it interesting, and the money quote is ”The term asthma is now consi

I was curious about the term, too. I found this [1], although it focused on asthma. I found it interesting, and the money quote is ”The term asthma is now considered an umbrella diagnosis for several diseases with distinct mechanistic pathways (endotypes) and variable clinical presentations (phenotypes)." [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6411459/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6411459/