What does "period" mean when someone says "Sth... Period"? [closed]

I often hear US citizens say something like this:

<Some phrases>. Period.

What does period mean when it appears in a sentence by itself in this type of situation?

Solution 1:

Period at the end of the sentence means, the things said in the sentence are definite and no change is allowed.

For example, "I want the document without any errors, period" meaning that there should not be any errors in the document.

Solution 2:

A period is what the full stop is called in American English. Saying period at the end of a sentence is a way of expressing the finality of what is being said. For example,

A: But phones are good for taking pictures.

B: No, I don't think so. Phones should only be used for communication, period.

Solution 3:

In your example, period is used as an interjection. As the Wiktionary explains:

Interjection
1) (chiefly North America) And nothing else; and nothing less; used for emphasis.

When I say "eat your dinner," it means "eat your dinner," period!

You usually use it to end a sentence/statement/command which you don't want to discuss/negotiate further.