Theoretically, a small business loan is an amount of money borrowed by a small business person to start or run a small business. Realistically, a small business loan is an euphemism used by lending institutions to describe personal loans given to small business people.
Consider that you may have an excellent credit rating and a solid business plan and still not be able to get a small business loan because you have no collateral. Even established business people can find themselves in this position, if they do not own enough tangible assets, such as houses or other property.
In other words, the small business loan is not being granted on the status of your business; it's being granted on your personal financial status. That's why it's important that your personal financial house is in order before you apply for a small business loan.
You will also find that many lenders just don't provide seed money. While they're perfectly willing to give a small business loan to help a business grow, they don't want to take the risk of lending to a start up.
All that being said, you can get a small business loan if you know where to look and are prepared to meet the lender's expectations.
If you're seeking a small business loan to start a business, see 8 Sources of Start Up Money.
And for more on increasing your chances of getting a small business loan, see How to Get a Small Business Loan.