Thats semantics.
When we say resolution of a display, it almost always means the native display resolution i.e. the horizontal X vertical number of pixels on the monitor/TV/whatever.
When we say resolution of a photo, we almost always mean the absolute pixel count of the photograph
Neither usage is incorrect.
DPI is entirely different- thats the density of the pixels per inch (if digital) or density of dots (if physical print) - and is not the end goal
When evaluating a display, there are three variables that come into play - the native display resolution, the size and the viewing distance
These three combine together to get you to the end goal - which is the PPD .. or pixels per degree
If you want the display to look good like printed paper, you would need a PPD of about 150 .. although 120 is also fine for most cases
this would translate - very roughly to
- a 4K 65"TV at 10 feet
- a 4K 32" monitor at 3.5 feet
- a 6.5" phone 1.5 feet
Agreed, it's semantics, but just because the whole world is using it doesn't make it correct or accurate. If you look at science or engineering, resolution has a whole different meaning. along with accuracy, precision and sensitivity.
This article is a little more spot on that the commonly used display resolution.
DPI is a unit. What does it define? What single word could you use that is the definition of the unit used as DPI? The
dictionary meaning of the word resolution. There are some definitions in tech which are inadequate or grossly incorrect, yet the usage persists because it's too common now to change.
Anyway, lets not get into an argument about what is being used vs what
should be used.
My point is pretty much what you wrote in the end.
Native display resolution, size and viewing distance. These three parameters are not enough to define quality. If they were, the main topic of this thread, TVs and monitors having the same three parameters would have identical image quality and usability. But they're not right? A 43" 4K TV and a 43" 4K monitor viewed at say 4' are not the same quality. Maybe just about adequate for video playback. So other factors too, like
@saggyN73 mentioned above about chroma subsampling, and the DPI/PPI i mentioned earlier are more important.