Learn English – Is “redact” an acceptable substitute for “delete” or “omit?”

I am constantly reading comments and documents from people who use the verb redact to refer to the act of deleting or otherwise censoring content. This never seemed correct to me, but until today it never actually occurred to me to look up the dictionary definition. I just did, and this is what it says:

–verb (used with object)
1.   to put into suitable literary form; revise; edit.
2.   to draw up or frame (a statement, proclamation, etc.).

Nowhere does this seem to indicate anything about deletion. I suppose that, in a very limited set of circumstances, redaction in the context of "editing for publication" might indeed involve the deletion of certain content, but that aspect seems incidental rather than fundamental.

That said, I accept that plenty of "common English" hasn't made it to the dictionaries or style guides yet, so I'm wondering if maybe I missed a memo, because the "delete" definition seems to come up almost everywhere I look. For example:

1. …before sharing board minutes (or shareholder or committee minutes) with auditors or other third parties, carefully review the minutes and redact (delete) sections containing privileged information to avoid waiving the attorney-client privilege. [AllBusiness]

2. The term redaction may not be a household term, but is often used in the legal community. It's the practice of removing confidential or sensitive data before giving the document to others. [ProductivityPortfolio]

3. On synonyms.net, it is actually defined as "edit" but has several "delete" synonyms listed:

   cast, edit out, edit, blue-pencil, cut, redact, put, frame, couch, delete

4. Adobe Acrobat even has a feature named Search and Redact that deletes results.

So… what exactly is going on here? Is this usage:

• Inane corp-speak parroted by people who have no idea what it means?
• Jargon that escaped from the legal profession and made it into common use?
• The result of most types of redaction being deletion, leading to natural confusion due to frequent use?
• A more mundane form of confusion – possibly with the similar-sounding retract?
• Just another case of the dictionary being at odds with the informal/spoken language?

Basically, what I'm trying to understand is: Is this really an acceptable usage of the word, and if so, then what is its real origin and/or justification?

_{Note: I'm having a little trouble making sense of the tagging conventions here, so please feel free to retag this if necessary.}