I assume that you mean startups when you say entrepreneurship. This answer will, therefore, focus on the similarities between small businesses and startups.But when you talk about similarities its better to mention differences too.

First, both face a lack of funds. They do not have money to throw around to solve a problem. Therefore they have to be very creative and innovative in solving the problems.

Next, they do not have adequate in-house resources to develop their products and services. For this, they would have to outsource work. Luckily, there are open source and shareable resources/services which have come up.

They are competing against industry leaders. Forget David and Goliath. This is more like an ant trying to wrestle a human. Therefore, they need to find niches in which the established players are not interested in yet.

They only have a few team members. One person may have multiple roles. For example, the small business proprietor may be the owner, the manager, the accountant, the supply chain guy. Similarly, the entrepreneur may be the CEO, the CFO, the CTO etc. etc. They have a very lean management model. Since only a few personnel run the company, decisions are quicker and actions are quicker.

Although you start out as a small business owner, somewhere along the way you either remain a SBO(small business owner) or you become an entrepreneur. If you are contented with earning enough profits to live a comfortable life and keep your business afloat, chances are you are a small business owner. This type of income replaces your income stream, which you earned from traditional employment. You really are not interested in growing or expanding your business. More than likely you will keep the business in your family. 

Maybe you are not satisfied with the status quo, and you are very ambitious and have the drive to go beyond just surviving. You would fit the definition of an entrepreneur. You will take more risks. Entrepreneurs enjoy learning through growing and expanding their businesses. Some establish businesses for the purpose of resale after realizing a certain amount of wealth. It may take a lifetime for a small business owner to earn wealth compared to approximately five years for a successful entrepreneur.

Another difference is how innovative are you. Small business owners are not the type to “think out the box”; whereas, entrepreneurs come up with new ideas, innovations, and products, as well as construct creative, strategic marketing plans. 

If you are the type who works in their business, you would be considered to be a small business owner. You are more repetitive. On the other hand, if you tend to strategically work on your business, evolving it, change target markets, if necessary, you are an entrepreneur. As a SBO, you tend to not change markets. In addition, your markets may be more general when compared with entrepreneurs who target markets are more focused. 

In regards to staffing, if you are a small business owner, you may have employees, which would involve having to pay employee-related expenses; such as, benefits and taxes. As an entrepreneur, you may choose to work with independent contractors rather than having employees work for you. 

There are some of you who tend to have characteristics of both groups. For example, as an entrepreneur, you may choose to keep the business in your family, just like a small business owner, rather than selling it. In addition to having this in common, there are similarities in operating your businesses. Both of you have to do some degree of advertising and marketing, as well as daily administrative functions. 

Overall, a notable difference is as a small business owner, you tend to need motivation; whereas, if you can be described as an entrepreneur, you are fuelled by ambition, drive and inspiration. Although similarities exist among the two groups, according to my research findings, the two terms are not interchangeable, and there are significant differences.