How does the UIS Governemnt define "Small Business"?

If you are in business and your business has less than 500 employees or less, you are eligible for The Small Business Administration (SBA) loan. So, that sounds like a good measure of small business.

However, if you are in healthcare indistry, This is what they say.
If you have 50 or fewer full-time equivalent (FTE) employees you’re considered a small business under the health care law.

I think if you have a privately owned company with 500 employees, you are not a small business. Bit that is me.