A few years ago, for most of us "start up" was a verb — it was something you did to a car. These days it's a noun. A startup is a new business, typically based on a new and untested idea.
One of the toughest things about a startup, the noun, is the verb — starting it up. The main obstacles are figuring out the best way to go about it, and how to pay for it. One place startups turn to start up is an angel investor. Having an angel investor is kind of like having a successful uncle who believes in you enough to give you some capital and guidance.