How do I understand company code in Fi?

In the fi module, I used to think that "company" and "Company"Code"Is a concept, thinking that a company has a company code, a company code represents a company, but today we see the sap fi module:

Company Represents an independent legal entity, composed of one or more company code.

Company Code Is a legal accounting entity. Determine the accounting year, currency, and tax report in the company code .

From this point of view, a company can have n company codes. I don't know how to reflect this situation in reality? This does not refer to the relationship between a group company and its subsidiaries. In my understanding, a company may have multiple accounting subjects. The company code is purely set up to differentiate accounting subjects, that is, the meaning of the company code is not what we call the company stock code.

I don't know which one can explain it to me?