Reason: Can we stop raping the English language and just invert the alias to thigh_highs? Just a thought, not sure why the conjunct spelling is the default one. In that case striped_thighhighs would need to be aliased to striped_thigh_highs too.
Well twintails is due to being re-romanized wasei-eigo (「ツインテール」). As far as I know "twintails" ≡ "long pigtails" or "a pair of ponytails" isn't commonly used in mainstream native English-speaking communities.
Our thighhighs tag is likewise in all likelihood a direct re-romanization of the Japanese-from-English 「サイハイ」 or 「サイハイソックス」 ("thighhigh socks"). In the beginning many tags were simply romanized Japanese even when there were English equivalents.
It's not clear to me that the garment has a clearly established name in English. Wikipedia refers to them with "hold-ups" as the primary title, and dictionary.com lists synonymous entries for "thighhigh", "thigh-high", and "thigh high". Google lists 12.2 million entries for "thighhigh", and only 1.4 million for "thigh high" and "thigh-high" which it conflates.
Basically I'd argue that "thighhighs" really isn't really a "rape" of the English language, so much as an alternative for a largely unestablished term, and that we ought to leave it as is. If we did for some reason decide we needed to change it, I find "thigh-highs" a much better alternative than the fully spaced out version.
Wikipedia refers to them with "hold-ups" as the primary title
I've never heard "hold-ups" used to refer to clothing. That article even says they're called "Thigh Highs in the USA". I'm not sure what the Danbooru consensus is on UK vs US spelling/terms (discussed briefly in forum #30125 and forum #33460) but "thigh-highs" is much easier to understand than "hold-ups".
I had never heard of "hold-ups" either before looking it up today, and certainly wasn't suggesting we use it. I only brought it up to show that there is far from a single established name for the garment. If I might re-iterate, my vote is a strong "nay" on changing the tag at all.
This message blatantly mixes up British and other English vocabularies, hope you get the idea.
I have noticed that, at least in practice, Danbooru uses thighhighs equally for thigh-level-high stockings (worn with garters), stay-ups (worn without garters) and over-knee socks (worn without garters). In my country, these three are considered entirely separate categories, even though related terminology is somewhat confused.
In real life, telling the difference between thick stay-ups and regular over-knees from a distance can be impossible; in the realm of manga/anime-style art, even more so. I have seen hundreds of pictures featuring Suwako, yet I have no idea which type she likes to wear.
The last example also serves to demonstrate that wearing stockings does not necessarily imply wearing a garter belt. (Yes, of course most of you know that better than I do!)
I am completely happy with thighhigs as it is, or with thigh-highs just as well. Just wanted to throw in my observations together with the terms I happen to be most familiar with and see if it calls forth any further discussion.
Eh sorry, but I'm not changing thighhighs and all the related tags and wikis. The argument against isn't strong enough or the problem (not that I feel there even is one) significant enough to be at all worth it.