What's great about the names for medical conditions is that the name is either latin or greek and is a description of the condition. Some diseases are given names by those who "discovered" them, but they also have a medical terminology name which would describe the symptoms or visual condition of a disease, condition, etc.
Pneumo: is pertaining to the lungs.
ia:Abnormal condition of
One issue regarding medicine is that health care professional often dumb down their speak with lay people. There are lots of people that still think you can "swallow your tongue".
When you look at pneumonia, many medical sites refer to it as an infection which isn't really the case. It's an inflammation. An infection can cause the inflammation. I know it may be splitting hairs but it is one reason that confusion exists and, in this case, JLM was somewhat surprised he got pneumonia.