What is a "double-pumper" carb?

[Sledge]

This week's dumb question:

I see the words "double-pumper" used frequently when discussing carbs. I've been doing all kinds of searches on the web, various carb manufacturer's sites, etc., but have not seen a definition.

For example, it looks to me like carbs with vacuum secondaries (like my Street Avenger 770 cfm) have power valves, while (at least some) carbs with mechanical secondaries seem to have accelerator pumps. It looks to me like the power valves and the accelerator pumps essentially perform the same functions, but again, I can't really tell based on my web searches.

So, what is a "double-pumper"? Does the term apply to carbs with mechanical secondaries only?

Is my Street Avenger a "double-pumper"?

Thanks in advance