What is another word for pneumonia?

There isn't really a true synonym for "pneumonia" in the sense of a single word that means exactly the same thing. However, depending on the context, you could use some related terms:

For informal use:

* Lung infection: This is a general term that encompasses pneumonia and other infections affecting the lungs.

* Chest infection: Similar to "lung infection," this is a broader term that could include pneumonia.

* Flu: While not the same thing, pneumonia is a common complication of the flu, so "flu" might be understood in this context.

For medical use:

* Pneumococcal pneumonia: This refers specifically to pneumonia caused by the pneumococcus bacteria.

* Bronchopneumonia: This type of pneumonia affects the bronchioles (small airways in the lungs).

* Lobar pneumonia: This type of pneumonia affects a whole lobe of the lung.

Ultimately, the best word to use depends on the specific situation and the level of formality required.