make more concise

[rubinovitz]

@evaz can you take a stab at this?

Criticism:
It's probably worth reading over and considering whether any part can be done inline to be generally more simple English. But for definitions, footnotes are definitely fine. Since it's in markdown, you can link them nicely anyway.

If you have any footnotes you want to add in making it more concise, feel free. Otherwise going to make separate issue for footnotes,