A full stop is a punctuation mark used in written English, and many other languages, to indicate the end of a sentence or the conclusion of a complete idea. Grammatically speaking, it is used to mark the end of a clause that is not directly connected to another clause. It can also be used in a number of other settings in written language, such as the indication of an abbreviation and in the formation of an ellipsis. The placement of a full stop within a quotation at the end of a sentence and the number of spaces used after such a stop can vary depending on the author’s chosen format and stylistic preference.
Also called a “period,” a full stop is one of the most common punctuation marks in English and is also one of the easiest marks to use. A full stop is generally used at the end of a sentence, as long as that sentence is not a question and is not meant to express an exclamation. The question or interrogative mark and exclamation point are used for these purposes instead. A simple clause typically ends with a full stop, though other marks can be used to join two or more clauses together as well, such as commas and colons.
The full stop can also be used in a few other settings within the English language, though these can vary somewhat. This mark is typically used after an abbreviation, such as “Co.” for “company,” “Sen.” for “senator,” and “Dr.” for “doctor.” In standard English, this usage is not always applied when the abbreviation begins and ends with the same letters used to begin and end the full word, such as “doctor.” It can also be used to form another mark called an ellipsis, which consists of three periods together “…” and usually indicates an incomplete thought.
There is some debate and personal preference over the use of other punctuation and spaces with a full stop in typed English. Previously, when using a typewriter, it was standard practice to create two spaces after the period at the end of a sentence. This allowed enough space to fully indicate the separation between sentences, rather than between two words. Computer word processing programs and printers, however, have a different natural spacing and so only a single space is typically used after a sentence today. Similarly, the full stop when used with a quotation at the end of a sentence can either go within the quotation marks or outside of them, depending on the preferences of a writer and the style he or she is using.