Full stop
The full stop (Commonwealth English), period (North American English), or full point (.), is a punctuation mark used for several purposes, most often to mark the end of a declarative sentence (as distinguished from a question or exclamation). A full stop is frequently used at the end of word abbreviations—in British usage, primarily truncations such as Rev., but not after contractions which retain the final letter such as Revd; in American English, it is used in both cases.