I'd call it a startup when you work fulltime on it, and it's designed for fast growth (as in Paul Graham's "Startup = Growth" essay, http://paulgraham.com/growth.html)

Venture funded is a big barrier, and filters a lot of startups. But it mostly filters them by personality type. I expect that most smart, extremely resourceful, good work ethic people could get venture funding if they wanted it. These attributes are what Y Combinator filters for. But the real correlate with success (and therefore money-making) is finding product/market fit. I think that's a lot harder than getting venture funding, and a lot more important.