The full point, full stop (British and broader Commonwealth English) or period (North American English) is a punctuation mark. It is used for several purposes, the most frequent of which is to mark the end of a declaratory sentence (as opposed to a question or exclamation); this sentence-terminal use is properly, or the precise meaning of, full stop.
This is a companion discussion topic for the original entry at http://grammarerror.com/tags/period