Is there a term for this phenomenon? (Scales with odd endpoints)

We’ve all seen the fast food drinks cup sizes that range medium, large, extra large, and jumbo with no “small”.
I just saw another one in my electric bill, where the day is divided up into “Mid Peak”, "Off peak"and “Super off peak”. No “Peak”. The legend on the bill shows all 24 hours of all 7 days fall into one of those three.

Is there a widely accepted term for labeling things this way? Using what one would linguistically assume was the middle as one end-point, and adding “extra/super” modifiers to the other end-point to extend the range?

What’s the term (if one exists)?

I don’t know the answer, but in regard to your electric bill, let me point out that many electric utilities only have “peak hour” rates during the summer, when there is a lot of demand for air-conditioning and refrigeration. The rest of the year, they have sub-peak rates.

There’s a term suppression of the zero for misleading graphical representations. Suppose you are plotting something that has increased slightly over time very slightly from 51% to 54%. The x-axis is time. If the y-axis runs from 0% to 100% then the graph is almost horizontal, showing little change. If you want to make it look like the change is more exciting, make the y-axis start at 50% (suppressing the zero) and run to 55%, so that the plot is a steep upward gradient.

But I don’t think what you’re talking about is really analogous to this. What you’re talking about is more like the “grade inflation” phenomenon in exams, or condom sizing! One end of the normal scale is perceived as undesirable for some reason, so the scale starts high and goes higher (or the opposite). I don’t know if there’s a term for this general phenomenon, but I think it should involve the word inflation.

“Marketing”

Your examples do not sound all that misleading, by the way. If the fast-food place has no small cups, only medium (i.e., pretty big) all the way to ludicrous, and that’s what they are calling them, then they’re not lying. The electric company has chosen the tiers mid-peak (= the middle of the Peak(s), like mid-winter), off-peak (a certain distance away from the peak), and super off-peak (admittedly silly-sounding since super means “above”; better to have called it far off-peak or low usage or something), and that covers the whole range of demand, nothing omitted.

Not quite the same thing, but the Mohs scale of mineral hardness is mostly linear, up until you get to diamond: Diamond, at Mohs 10, is nearly 5 times as hard as corundum, Mohs 9.

I don’t know if they still sell them in these sizes, but laundry detergent had King as the smallest box size going up to Family as the largest. Not sure what the intermediate sizes were.

The middle of the peak (Mid Peak) is the peak. Or am I missing something?

Yes, I remember when I was a kid, noticing that the smallest sized box of detergent was labeled “Giant” size.

This could be an example of the Decoy Effect.

This is a good point. Soft drinks from a fountain are often sold in sizes that, given a normal human’s capacity to consume liquid, run from “large” to “swimming pool”. I think movie theaters are notable for this.

Whereas something like the “grade inflation” of exam results really is misrepresentation, the middle of the scale no longer maps to average human ability.

If one cup holds less than the others then it is by definition the small cup. How they label them is marketing BS, or the decoy effect.

Well, no. A size descriptor may refer to the entire normal range, not just size relative to what’s immediately available. A specialist “Big & Tall” clothing store does not relabel clothing S-M-L with everything scaled up, it labels L-XL-XXL to remain consistent with general labeling in non-specialized stores.

That might be true, if there were some industry-wide standard that a “small cup” is 8 oz, a “medium” is 12 oz, and so on. If there were such a standard, then a vendor whose smallest cup was 16 oz would indeed be serving a “large” (and possibly an “extra-large” and so on). But there is no such standard for drink sizes.

Try buying womens jeans. Size is just a number. They mean absolutely NOTHING.
Gotta try on. So frustrating!!

You would have to know the drink, too. If they are slinging espresso, 8 oz is not “small”. For Coca-Cola, I don’t know, but if 8 oz is a “normal” serving, do you want to call that “medium” because any less would be a small amount, or “small” because that’s the smallest normal bottle? Either way the industry would need to specify standard serving sizes, not standard cup sizes.

Re. clothes, you have always needed to try them on anyway as designers cut them differently, plus the sizing scale varies by country, but what you have there is 100% size inflation. Men too.