Word for something that is either transparent or opaque, but can describe both [closed]

Question

This word would cover everything from completely transparent glass to the kind of opaque glass that you would get in a bathroom. I first thought that opaque would cover the definition, but it appears to specifically apply to a material that you can't see through.

Answer 1

The closest I can get would be "degree of opacity". It can range from no opacity at all (total transparency) to totally opaque (zero transparency).

• Opacity is the measure of impenetrability to electromagnetic or other kinds of radiation, especially visible light. Wikipedia

Answer 2

There is no word that simultaneously means something opaque and something transparent. The only way this question makes sense is if you're asking for a word that covers degree of transparency/opacity. Otherwise the question is total nonsense or this is an incredibly strange and actually somewhat brilliant troll.

Answer 3

Translucent!-(of a substance) allowing light, but not detailed images, to pass through; semitransparent. "fry until the onions become translucent" synonyms: semitransparent, semiopaque, pellucid, limpid, clear; More

Answer 4

My dictionary has for German lichtdurchlässig (letting light pass through) the words translucent, pervious to light, light-transmissive.

By the way, opaque lets through light. There are garden lamps with opaque bowls, but they light the garden.

Answer 5

The word you are looking for is "opacity."

The dictionary definition of it tends to refer to lack of transparency, but this is a good example of why a dictionary is not always the best place for learning language. Unlike "opaque," actual usage of "opacity" often covers a spectrum and not a single state. In other words, if you ask "What is the opacity of this type of plastic?" the range of possibilities includes everything from full opacity to full transparency.

Answer 6

Perhaps you could use:

optical density:

(physics) a measure of the extent to which a substance transmits light or other electromagnetic radiation (TFD).

The logic is simple: to see an object on the other side of your material the light has to travel from your side, through the material to that object, and then back to your eye. Higher optical density means that it will be more difficult for light to travel, therefore it will be more difficult for you to see the object.

The optical density of a completely transparent object (100% of light goes straight through) is zero.

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Two concerns with this word:

• It isn't exactly a single word (I wouldn't call it a compound noun), but it is a single term.

• Although dictionary definitions state that it is a term borrowed from physics, scientific discourse regarding physics is the only occasion where you shouldn't use this term. Here's why:

Some dictionaries (e.g. Collins) say that this is an old term for two different terms:

reflection density

(physics) a measure of the extent to which a surface reflects light or other electromagnetic radiation, equal to the logarithm to base ten of the reciprocal of the reflectance D Former name: optical density

and

transmission density:

(physics) a measure of the extent to which a substance transmits light or other electromagnetic radiation, equal to the logarithm to base ten of the reciprocal of the transmittance τ Former name: optical density

(today this is also called absorbance - A)

If you are talking to physicists, they would expect you to know which of these two measures you are talking about. But in other contexts it makes no difference whether the light is diverted (or in an extreme case reflected) - which corresponds to reflection density, or it is absorbed - which corresponds to transmission density, either way it doesn't freely pass through your material, and it makes it difficult to see the object on the other side (or the opposite: if the optical density is low, the light is neither reflected nor absorbed and you see the object on the other side clearly).

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EDIT (from OP's comments): You would like something that describes the whole range of transparency/opacity from completely transparent to completely non-transparent (completely opaque), but you don't want it to be a measure. I'm afraid that this is not possible - because you are looking for a term to describe one of the two extremes or anything in between. Something that can be scaled, graded - can be measured. It isn't like colour, which is a hypernym for red, green, yellow, blue, purple, red, orange etc. because you don't have a whole set of elements from which to choose - you have only two opposite elements (like black/white (light/dark) and all the shades of gray in between).

I therefore stand by my suggestion optical density because it can describe the whole range while it doesn't suggest that the object is closer to one end of the scale, it is somewhat more neutral then opacity/transparency (although both of these terms are also quite good).