no, not correct.
1080 tells you, that the vertical resolution is 1080 lines. nothing more, nothing less.
so if i say, i have a 1080 screen, its just that. 1080 vertical lines.
it wont tell you if its 16 or 21:9, unless you name the horizontal resolution as well...
please show me, where the international standard says that a vertical res of 1080 is always 16:9.
same with UHD: i can have 4096 (native 4k) and 3840 (UHD) which will give you 21 und 16:9 ration,
while horizontal res is 2160 for both.
so saying your screen is a 2160 res, wont tell anything about the ratio.