The punctuation in a Bible reference isn't called anything special beyond simply "punctuation." It's just regular punctuation used to make the reference clear. The common punctuation marks used are:
* Colon (:): Separates the chapter and verse(s). (e.g., John 3:16)
* Comma (,): Separates multiple verses within the same chapter. (e.g., John 3:16, 18)
* Dash (–): Indicates a range of verses. (e.g., John 3:16–18)
* Period (.): Used to indicate the end of the reference. (e.g., John 3:16.)
So, there is no specific name for punctuation in a Bible reference. They are just regular punctuation marks doing their job of providing structure and clarity.