carved in stone

carve (something) in stone

To make something permanent and incapable of being changed, typically a plan or idea. We might get brunch next weekend, but we haven't carved anything in stone yet.

See also: carve, stone

carved in stone

Permanently fixed or firmly established; incapable of being changed. Often used in the negative. The deal isn't yet carved in stone, but we're confident it will go ahead as hoped.

See also: carve, stone

carved in stone

 and engraved in stone; written in stone

Fig. permanent or not subject to change. (Often in the negative.) Now, this isn't carved in stone yet, but this looks like the way it's going to be. Is this policy carved in stone, or can it still be modified?

See also: carve, stone