From the “Notre Dame Victory March”:
What is a “volley cheer”? Does the phrase mean anything in particular?
I think it just means a bunch of people cheering, as in a volley of arrows, or a musket volley.
Definition 2 seems to work: A bursting forth of many things together: a volley of oaths.
Edit: Also, I know it as “Send a volley cheer on high.”
But we take what we can get at Notre Dame, these days.