Unbreakable said:
To be honest I always thought sheer was referring to a special kind of material that is always see-through compared to any random material "drawn" as see-through, if there is no real difference to them (either material or definition) I don't mind having them aliased but if people can provide arguments for not doing it I don't mind either.
Sheerness is related to the density of the fibers, not the type of material itself. Typically, sheer hosiery is around 20-30 denier, and anything 40 denier or higher is opaque. You can make sheer fabric out of silk, nylon, gossamer, etc.
There may be a need to distinguish between sheer fabrics and non-woven materials such as transparent latex, but most of the posts tagged transparent_skirt clearly refer to the former.