Cavernous

Dark, empty space: an echoing chamber, not a color.

#515252

Cavernous is a neutral grey.

It can be described as neutral, medium and colorless.

Set in white, because white reads best on it.

Cavernous

Cavernous sinus

The cavernous sinus within the human head is one of the dural venous sinuses creating a cavity called the lateral sellar compartment bordered by the temporal bone of the skull and the sphenoid bone, lateral to the sella turcica.

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cavernous

Adjective

Resembling a cavern in size, shape, or atmosphere.
Giving the impression of vast, dark depths.

Wiktionary

Its neighbors.

Celluloid, #515153 Blank Space, #505150 Cracked Pepper, #4f5152 Briquette Grey, #515051 Muted Ebony, #515453 Satin Black, #4e5152 Fiftieth Shade of Grey, #505050 Black Space, #545354 Greyish Black, #555152 Lump of Coal, #4e5154 German Grey, #53504e Magnet, #525054

Cavernous

#515252

Cavernous

Cavernous sinus

cavernous

Its neighbors.

Its complements.

As a ramp.