Retina means high pixel density, not high resolution. And there are very few standalone displays on the market which can be called “retina”, unfortunately.
Interestingly, I would venture to say that DPI is a measure of resolution: that's the way it's still used in printers or scanners, for example (600 dpi). And retina instead means high angular resolution, or pixels having small arc measures from "appropriate" distances.
The term "resolution" transitioned gradually to mean number-of-individual-lines-rendered horizontally and vertically for displays, but really, the idea is how many dots can you "resolve" (or "resolving power"): a "high resolution" screen or screen mode had a larger number of individual pixels being drawn, which meant that the density is higher. You never talk about a scanner having a resolution of 7200x3600 even if it can scan 12"x6" at 600dpi.
So really, in an informal conversation, I believe both are fine. If you want to be extremely precise, you missed the mark: width and height in pixels is the sanest way to call what you refer to as "resolution".
> For device displays such as phones, tablets, monitors and televisions, the use of the term display resolution as defined above is a misnomer, though common. The term display resolution is usually used to mean pixel dimensions, the maximum number of pixels in each dimension (e.g. 1920 × 1080), which does not tell anything about the pixel density of the display on which the image is actually formed: resolution properly refers to the pixel density, the number of pixels per unit distance or area, not the total number of pixels. In digital measurement, the display resolution would be given in pixels per inch (PPI).
The term "resolution" transitioned gradually to mean number-of-individual-lines-rendered horizontally and vertically for displays, but really, the idea is how many dots can you "resolve" (or "resolving power"): a "high resolution" screen or screen mode had a larger number of individual pixels being drawn, which meant that the density is higher. You never talk about a scanner having a resolution of 7200x3600 even if it can scan 12"x6" at 600dpi.
So really, in an informal conversation, I believe both are fine. If you want to be extremely precise, you missed the mark: width and height in pixels is the sanest way to call what you refer to as "resolution".