What is a Period?
Called a full stop in British English, the period is one we are all too familiar with right from the outset of learning how to read and write. And thankfully, unlike semicolons and commas, the rules governing the use of periods are matchlessly simple.
What Does a Period Do?
Question marks end an interrogative question/statement. But ending a declarative statement is what comes to mind when using a period. The following are basic examples of ending declarative statements with a period
He is a skillful player. We shall see tomorrow. I love salads. Pasta is delightfully sumptuous.
Periods and Quotation Marks
Periods are pretty simple to use. The only concern writers have is where to place them when there are other nearby punctuations. When ending a sentence in American English, periods go inside the closing quotation mark. Thus;
The professor said, "Only hard work guarantees success."
Periods and Parentheses
Periods go before the closing parentheses when parentheses enclose a complete, independent sentence. E.g.
He doesn't want to see him. (I should have done more to convince him.) Nonetheless, I hope the misunderstanding is resolved amicably.
However, the period goes on the outside when the elements in parenthesis are nested in another sentence. I.e.
He went shopping but couldn't find his credit card (his worst nightmare).
Ellipses (singular: ellipsis) are similar to the period but contain three dots in a row. They are principally used to shorten sentences when omitting parts of a quote or just to indicate a dramatic pause. Here's an example:
The professor advised us to "always study . . . to pass our examinations."
In this example, the words "day and night" have been intentionally omitted from the flow of the sentence. This is occasionally done if the omitted words are not significant or make it harder to understand the desired context. Thus, an ellipsis informs that you've left something out.