Markup might be defined, as it being information made in the marking of a document, such that the marking would be made as expressions, indicating such that is not implied, distinctly, in the text of the document.
There are systems of proofreaders's marks. There are some references, about such, from Miriam Webster and from Prentice Hall.
One might apply something like a simple markup langauge, in some of one's own handwriting.
Pages in this topic: DSSSL Scribe
Also linked from: Document Formats
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