Notation
Notations seem to be a more specific meaning of Mediums, which will probably be more useful in defining Readwise/Books/Tools for Thought.
Linus Lee's essay on Notational Intelligence lays it out fairly convincingly. He defines notations as:
some arrangement of symbols or images that we use to record and communicate ideas, and the way we interact with those symbols in our thinking process.
Good provoking questions:
"What good ideas can we take from this to our vision of better notation, better documents, and better ways of working with ideas?"
Mediums seem to be closely related to the idea of media, or the raw materials which something is constituted from. The media also has certain inherent capabilities.
What's the difference between medium and notation?