Venture capital is a type of funding for a new or growing business. It usually comes from venture capital firms that specialize in building high risk financial portfolios. With venture capital, the venture capital firm gives funding to the startup company in exchange for equity in the startup. This is most commonly found in high growth technology industries like biotech and software.
A person who deals in venture capital is a venture capitalist, and usually works for a venture capital firm.
With a loan, a lender gives a company money, and the company has a contractual obligation to pay back that amount plus interest over some period of time. Sometimes the loan is backed by assets (like equipment or inventory) or receivables. In the case of many small businesses, the loan is backed by a personal guarantee from the business owner. This backing allows the lender to recoup some of its investment in case the lendee defaults (fails to make payments)
With venture capital, the startup company issues private shares in exchange for money.
Timing. Venture capital is typically not used for extremely early funding. Instead, these rounds are often called "Series AA," or "Pre-A" rounds, and include funding from friends & family, angel investors, and seed stage financing syndicates and firms. Venture capital firms usually get involved at the Series A round and after (all happening after the AA or Pre-A rounds). Although both VC and seed/angel investing are high risk investments, seed & angel investing usually happen in the earliest stages of a startup when the risk is ultra-high.
Funding Amounts. Venture capital also usually starts with companies that are slightly more mature (although not necessarily profitable), with higher valuations, and higher funding amounts. Funding amounts in angel & seed investing typically range from a couple thousand USD through to one million USD, while venture capital is usually millions, tens of millions, or even hundreds of millions of dollars.
Deal Structure. Angel investing also frequently uses different deal structures than VC, although this is primarily to reduce legal costs, cut transaction overhead, and rapidly accelerate the rate at which the startup and angel investor can agree on terms. Some of these alternative structures include convertible notes and SAFEs ("simple agreement for future equity"). Unlike venture capital, convertible notes and SAFEs don't actually transfer equity in the company to the investor until a later date, and in the case of failed startups, sometimes not even at all.
The primary difference between venture capital and crowdfunding is simply equity. Venture capitalists acquire equity in the startup. Crowdfunders do not. Instead, crowdfunding is much more like a high-risk pre-order platform, where there's a reasonable probability that the startup may fail to deliver the pre-order.