Cubic isn’t a measure at all, it’s a shape.

I don’t think I said it was a mass.

I meant cubic as in cube shaped?

Super pedantic edit:

Now that I think about it cubic isn’t really a measure of volume :

“cubic” on its own is not a measure of volume. It is an adjective that describes something related to a cube or three-dimensional space, but it requires a unit of length to provide a meaningful measure of volume.