Greyness and Half-light

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

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

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

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