Formats
A format is a shape that has already decided part of what belongs in it.
It has also decided part of what it will not hold. What goes in is yours. The rules come with the shape. Each one is written down: a page at most, plain text, free. They name no course and no year.
A brief can be a format. An interview is a format. A monologue is a format.
A specification is another, and the only one written down here so far.
A specification, in nine lines
A description of a thing that does not exist yet, in your own words, complete enough that somebody or something else could build it from it.