Where did the convention of naming command line arguments as 'argv' come from?

Question

It seems like Python, PHP, and Ruby all use the name "argv" to refer to the list of command line arguments. Where does the name "argv" come from? Why not something like "args"?

My guess is that it comes from C, where the v would stand for "vector". Wikipedia has a footnote that says:

the vector term in this variable's name is used in traditional sense to refer to strings.

However, there isn't any source for this info. Really, I'm curious if it has roots that trace even farther back. Did C use it because something before that used it?