By dictionary terms, an entrepreneur is someone who starts a business, risking their own money in hopes of making a profit. A freelancer is someone who is self-employed and hired by different companies for specific projects.
Entrepreneurs find a gap or unmet need in the market, come up with an idea, and then try to turn it into reality. Freelancers, instead, usually compete within an existing market, selling their skills to businesses who need their help. Also, entrepreneurs are usually building a business in order to sell it off someday, whereas freelancers are focused on building a client base for themselves long-term.
Freelancers can easily and often do turn into entrepreneurs. When there's more work coming in than you can handle, you essentially have 2 choices: Either hire some people to help you or turn down the work. If you hire people to help, you've in many ways become an entrepreneur. If you prefer to work within your own workload and abilities, you are choosing to remain a freelancer.