Carnival Glass is (press) moulded, iridised glass with a pattern. It can have any base colour at all - the crucial attribute is that the glass must be iridised.
Your comport does not appear to be iridised, hence it's not Carnival Glass.
The pieces that you've seen where amberina and carnival are mentioned in the same listing will be where the base glass colour (selenium red) is also iridised. L E Smith who make the contemporary version of the Windmill pattern (the pattern was originally made by Imperial) are well known for their red Carnival Glass.
This all brings us to another tricky subject. The colour "amberina" means slightly different things. There is a purist meaning, which was first patented by Locke and Libbey in 1873. To quote Revi ("Nineteenth Century Glass") - "It was the first patented method for producing shaded and parti-colored glassware from a sensitive, homogenous metal. A very small amount of gold in the solution was colloidally dispersed in a transparent amber batch". Revi goes on to explain how the glass was then cooled and re-heated so that "this rapid cooling and reheating struck a red color in the reheated portions, casuing in the finished product a shading of amber to ruby red".
Now, red Carnival Glass was not made until the 1920s - it was around then that the use of selenium in the glass batch allowed pressed glass to be made in the colour red. It is also heat sensitive - and must be "struck" in exactly the same way as described above. The actual process was named "striking to another colour" or "striking" for short. The process relies on the introduction of chemicals to the glass batch that will ultimately change the colour of all or part of the glass item.
I'll quote now, to explain how it is done (Thistlewood "The Art of Carnival Glass"): "Pressed red is a difficult color to achieve with absolute uniformity as it is notoriously difficult to strike. When selenium red is taken from the hot glass batch it is red. However, when it is then pressed in a mould, its color becomes yellow. Subsequent re-heating causes the yellow color to change back to redâ€”technically, what happens is that the crystals within the glass are made smaller by pressingâ€”this causes the color change to yellow. They are then made larger by controlled re-heating, which in turn causes the yellow color to become darker and go back to red.
Itâ€™s not unusual to find a yellow shading on red Carnival Glass where the heat has not been great enough on that portion of the item being made. The shading into yellow is called amberina. Standard amberina is where the outer edges of the piece are red but as you look toward the center of the item you see an increasing amount of yellow. Reverse amberina is the opposite way roundâ€”the yellow tones are to the outer edge of the piece."
When this glass is iridised, then it's either red Carnival (if it is all red), and amberina or reverse amberina Carnival (where there is red shading).
I'm not sure if I have fully answered your question, Barbara, so please ask again if I can help any further.