Grayness and Half-light

Grayness noun - A neutral achromatic color midway between white and black.

Half-light and grayness are semantically related. In some cases you can use "Half-light" instead a noun "Grayness".

Half-light noun - A greyish light (as at dawn or dusk or in dim interiors).

Grayness and half-light are semantically related. Sometimes you can use "Grayness" instead a noun phrase "Half-light".