> A corporation is an organization—usually a group of people or a company—authorized by the state to act as a single entity (a legal entity recognized by private and public law 'born out of statute"; a legal person in legal context) and recognized as such in law for certain purposes.[1]:10 Early incorporated entities were established by charter (i.e. by an ad hoc act granted by a monarch or passed by a parliament or legislature).
Webster's 1913:
> A body politic or corporate, formed and authorized by law to act as a single person, and endowed by law with the capacity of succession; a society having the capacity of transacting business as an individual.
Modern Merriam-Webster's retains essentially the same definition.
That's why I hold that position about their relationship with the rest of society, and in particular with their parent government. I'll grant some other kind of organization, not being definitionally a creation of government, may not have the same relationship.
This can be common law, recognizing the legal authority the shareholders grant the corporate entity to act on their behalf.
There is a common law justification to treat that entity as a legal person because it acts as a single entity, as willed by the shareholders.
I am not suggesting that the corporate legal structure has never come into existence by legislation. I am just saying that the corporate structure can also emerge entirely through the common law enforcement of contracts.