The particular sense of medium I have in mind is the one used in
Water is a medium of sound propagation.
But propagation implies a multiplicity of places, or at least two of them, so that if something propagates then it goes from place A to B.
But suppose a thing simply exists in another. For example sound may now exist in a body of water (having already propagated to all places in it). In which case, we might say:
This body of water is a medium of sound's existence.
If medium simply requires some sort of movement, maybe:
This body of water is a substratum of sound's existence.
Ideally I am looking for a word (in Latin and Greek) that means a thing in which another may either propagate or exist.
More examples:
- A crowd is a medium of hysteria's propagation.
- A human breast is a medium (or substratum) of love's existence.
- A (financial) account is a medium of (financial) delinquency's existence.
- A network of accounts is a medium of delinquency's propagation.