What is the shorter version of reverend?

Answer 1

Without the apostrophe, yes; thus: Revd. John Smith. If you're seeing "rev'd" it could be an abbreviated form of "revised" (depending on the context, of course!)

Answer 2

The abbreviation for "revision" is "rev.".

Answer 3

The term for a clergyman (capitalized if a title or address) is spelled reverend.

Answer 4

Rev.