What do the "V." and the "R." stand for in the old prayer books?

[Scoochy]

What do the “V.” and the “R.” stand for in the old prayer books, or in their FIRST printed (or written) usages?

I think, but can’t prove, that they stand for:
V: Versicle
R: Responsorial

I’ve had this question ever since my youth, & decided that it was past-time to get a correct, historical answer.
Thank you.

 

[AndrewAxland]

They are medieval Latin abbreviations for the words “versiculus” and “responsum”, or “versicle” and “response” in English, originally in reference to the antiphonal recitation of psalms.

 

[Scoochy]

THANK YOU, AndrewAxland!! So much appreciated. When you have a nagging question, all your life, & you FINALLY get the answer, there is light & freedom. JMJ✝

 

[Christmysavor]

V/ priest part
R/people’s response

 

[Scoochy]

Yes. Didn’t you ever wonder what those letters stood for. All these acronyms drive me nuts. SIM, PIN, HTTP, URL, etc.