What is the difference between a territory and a state?
In the United States, a State is a defined geographical area that has been recognized as a full member of the Union established by the Constitution, and thus a sovereign entity within that union.
A territory, on the other hand, is a geographical region that is subject to the sovereign control of the United States but has not been organized and accepted as a full partner and sovereign entity within the union and is, therefore, more subject to direct control by the Congress and the President, than is a State.
Residents of a territory, although citizens of the United states, may not be eligible to vote for their governor or legislature, or for the President, although some can, and may not have voting representation in the Congress.
Only the very technical difference that the "municipal corporation" is the legal entity comprising the government, and the municipality is the territory which forms the jurisdiction of the municipal corporation. It is like the difference between "state" (in the sense of "head of state", not a division of the United States) and "country". Very technical.