Aliasing tights → pantyhose
Link to alias

Reason:

The difference between pantyhose and tights seems to be in thickness/opacity, with no clear dividing line between the two. I think grouping these under pantyhose makes sense, as it has the cleanest definition (that being 'sheer tights', with anything sheerer still considered pantyhose until you reach 'nothing'). This will at least bring them together under the same class of garment, letting the viewer make the judgment for themselves.

That still leaves some ambiguity at the thicker/opaque end, so maybe tights could be later be made a subset e.g. 'particularly thick/opaque pantyhose', but again, there's no objective line on that end.

-1

Pantyhose are a type of tights but not all tights are pantyhose.

I will agree with the tagging of tights being wildly inconsistent though, and would require a full manual cleanup beforehand if this alias was implemented.
It would probably be better off to send tights to a disambiguation.

If a pair of pantyhose is about 10 sizes too big for the guy wearing them, can you still call it tights?

+1 for disambig.

I agree that tights is the more encompassing term, though I think the term pantyhose is in common enough usage (in language) and distinct enough from its parent set that it's worth keeping. I'm not wedded to the idea of aliasing these just yet either.

Ideally, tagging something like sheer_legwear + tights would cover the distinction, but there's some cleanup needed there, too (like implicating sheer_legwear to transparent_legwear, a la sheer_clothing and transparent_clothing), and tights needs to be tidied up in either case.

Edit: Alternatively, we could simply have pantyhose imply tights and also sheer_legwear, leaving tights as the catch-all for waist-high hosiery of any degree of sheerness/opacity. I feel like this cuts to the heart of the ambiguity, and also allows both commonly-used terms to be preserved.