If two objects in close proximity create an area of shade which is contiguous, would you call this a shadow or shadows? For example, which of the following sentences are correct, assuming that multiple palm trees create a contiguous shaded area:

The crowd gathered in the palm trees' shadow.

or

The crowd gathered in the palm trees' shadows.

My intuition is that it is the former (assuming the palm trees create one contiguous shaded area). If that's correct, when would you use shadows? When the shaded areas become non-contiguous? When the two objects are grouped separately?

If I'm wrong, what is the rule? Does the numerosity of "shadow" have to follow the numerosity of the objects which create the shade? Consider a case where at first I see a shaded area without knowing what is casting the shade. I would obviously just call it a "shadow." But if I then learn that there are multiple distinct objects creating the shade, would I then have to say "shadows?" That would be awkward.

I'm not interested in the figurative usage of the word "shadows," nor any usage where "shadows" does not mean multiple "dark areas or shapes produced by a body coming between rays of light and a surface."

• You are overthinking this. There is no rule. If the person speaking thinks of there being one shadow they use singular, otherwise plural. Also "shadow" can be a mass noun, so singular is usually acceptable. Jun 3, 2017 at 2:40
• Here's an Ngram for "shadow of" and "shadows of". Click on the links at the bottom to see how others use the singular and plural forms (even though many of them are metaphoric). Jun 3, 2017 at 3:12
• @DJClayworth Would you say that when the shaded regions are non-contiguous, it could still be just "a shadow?"
– Evan
Jun 5, 2017 at 0:24
• @Evan I might or might not, and someone else might decide differently. Also note that "a shadow" is different from "the shadow". Jun 5, 2017 at 0:40
• @Lawrence, an Ngram link is helpful, but here's the one for "~ of the trees", which is much more evenly split.
– lly
Jun 10, 2017 at 9:07

Generally, you can use your discretion in deciding whether to consider a silhouetted space a singular shadow or multiple shadows. You might consider thinking of it like the word "shape," which likewise can apply with different levels of granularity. You could say, "Look at the shape of the palm trees," referring to the shape of the cluster of trees as a whole, or you could say "Look at the shapes of the palm trees." You could even describe a singular object as having multiple shapes or shadows.

I looked at the shadow of the tree.

I looked at the shadows of the tree.

It's also worth noting, however, that "shadows" plural can carry a meaning distinct from "shadow" singular, referring to darkness generally. Merriam-Webster provides this definition:

7 shadows plural : dark 1a

Consider as an example this figurative use in a headline from The New York Times:

Once in the Shadows, Europe’s Neo-Fascists Are Re-emerging

• Thanks, but I'm hoping to get some sources here. I'm also not interested in the meaning of "shadows" which does not mean multiple shadows. I'm especially not interested in figurative usage of the word.
– Evan
Jun 9, 2017 at 18:37
• @Evan Fwiw, the figurative use is in reference to multiple shadows. It's just generically referring to a place of darkness created by many shadows. It's not going to apply to trees, but it's worth noting the negative figurative connotation of the plural form.
– lly
Jun 10, 2017 at 6:23

'Shadow' is plural when you think it is.

This really isn't as difficult or unusual as you're making it out to be. Think of a much more common and intuitive example of the same idea: hair.

It's not grammatically incorrect to say

Her hairs are long.

but syntactically it focuses on the individual hairs in a very uncommon way. Native English speakers don't usually think of hairs as individuals, so we speak of them as a mass:

His hair is long.

For the most part, English considers things that are easily counted as countable and stuff that isn't as uncountable. If the shadows are discrete, it would be natural to speak of "the shadows" and if they formed a single mass shadow, it would be natural to speak of "the shadow" just as all the world's inlets, seas, and oceans coalesce into "the sea" or "the ocean". To native speakers,

The crowd gathered in the shadow of the palm trees.

and

The crowd gathered in the shadows of the palm trees.

are both fine but mean different things.

The first creates a very definite sense that the trees' canopy is more clustered and full, casting a single great shadow upon the ground. The second creates the opposite sense that the shadows are more discrete, either because the trees are separate enough to form no canopy at all and people gather separately under separate shadows or because the mass shadow is spotty in some way that makes the individual shadows noticeable. (In my own mind's eye, I still see a single canopy, but with a sinking sun causing the shadows of the separate palm trunks to be more noticeable; other readers would probably have different images but the point stands.)

If it helps, the base definition of shadow at the OED is not "the darkened area created by obstructed sunlight". It's

Comparative darkness.

Just like water, sand, hair, flour, and darkness, it defaults to being uncountable. It only feels different because it's so much easier to think of separate discrete instances of shadow. But it's just like a restaurant offering to bring four [glasses of] waters, Arabia having its [several patches of different] sands, the [instances of] hairs growing on someone's nose, a store selling four [brands of] flours, or the [species of] darknesses which are ignorance, unkindness, and incuriosity. They can still be plural when it makes sense for them to be discussed as discrete examples or types of the mass they usually represent.

If two objects in close proximity create an area of shade which is contiguous, i think the appropriate one would be ''shadow''. But if its far apart we can call it 'shadows'.