Full stop (period) - a terminal point that indicates to the reader that a sentence is finished.
Known in American English as a period, a full stop is the most straightforward punctuation mark.
A full stop is used to show that a sentence is finished. This indicates to the reader that a complete thought has been expressed and that subsequent thoughts will be outlined in subsequent sentences.
If the current sentence also concludes the discussion of a particular topic, subsequent sentences should be placed in a new paragraph.
If a sentence ends with a word that already includes a full stop, question mark, or exclamation mark, we do not need to add an additional full stop.
Incorrect
My favourite rapper is the Notorious B.I.G..
The report is titled How Can We Improve Punctuation?.
I just finished watching the film Shazam!.
Correct
My favourite rapper is the Notorious B.I.G.
The report is titled How can we Improve Punctuation?
I just finished watching the film Shazam!
If a sentence ends with a word or phrase in brackets, the full stop should be placed outside the brackets.
Incorrect
You should always check the weather before leaving the house (even if it is sunny.)
Correct
You should always check the weather before leaving the house (even if it is sunny).
However, if an entire sentence is placed within brackets, the full stop should be placed inside the brackets.
Incorrect
Morning is the best time of the day to exercise. (This is assuming we can get out of bed).
Correct
Morning is the best time of the day to exercise. (This is assuming we can get out of bed.)
If a sentence ends with a quotation, the full stop should be placed within the quotation mark.
Incorrect
Barack Obama's presidential campaign used the slogan "Yes we can".
Correct
Barack Obama's presidential campaign used the slogan "Yes we can."
Generally, if an abbreviation includes lowercase letters, a full stop is used to end it.
Examples
Mrs.
Aus.
etc.
However, if an abbreviation includes only uppercase letters no full stop is required.
Examples
NASA
USSR
UN
These days, only one space is expected after a full stop.
In the past (before the advent of the computer) it was common to use two spaces after a full stop in typed English.