( foundation stones)
1.
A foundation stone is a large block of stone built into a large public building near the bottom. It is often involved in a ceremony for the opening of the building, and has writing on it recording this. ( mainly BRIT; in AM, use cornerstone )
The Princess of Wales laid the foundation stone for the extension to the Cathedral.
N-COUNT : oft with poss
2.
The foundation stone of something is the basic, important thing which its existence or success depends on.
...these foundation stones of the future: education, training, research, development.
N-COUNT : usu N of n