Meaning of proprietorship

Good afternoon everybody, how are things with you? I’ve just read the following sentence:
I recently quit my day job and started my own proprietorship.

Please, I’d like to know what the word proprietorship means in this context. I figure it must be a company or business enterprise? If so what is the difference between start a business/company and start a proprietorship? Also, according to my dictionary proprietorship means ‘ownership’ or possession’. Now, you can’t really start an ownership, can you? Or maybe you can? OK, I’ve googled a bit around and here is what I’ve found:

Should I register a trade name, a proprietorship or incorporate the business and why?

So, it seems a proprietorship is some kind of legal entity? And what about incorporte the business? What exactly does that mean? I appreciate any of your thoughts on this issue.

Anyway, enjoy your Sunday and see you soon!

A proprietorship is an unincorporated business owned by a single person who is responsible for its liabilities and entitled to its profits.
A corporation is a type of business organization chartered by a state and given many rights of a separate entity. The owner has limited liability. Lenders prefer to deal with a corporation, rather than a sole proprietorship.