Dots are used singly or with other dots and other symbols to form six separate and distinct elements of punctuation: A period, a semicolon, a colon, an ellipsis, a question mark and an exclamation point.
The period, a single dot, is used to indicate the end of a sentence. A proofreader may suggest the insertion of a period where one has been omitted or where she believes a run-on sentence should be concluded.
At the suggested point of insertion, the proofreader draws---beneath the sentence and pointing upward---a caret, which looks like the letter "v" turned upside-down. In the right-hand margin of the document, at a point corresponding with the caret, the proofreader places a dot and draws a circle around it. The empty caret directs the author's attention to the suggested punctuation.
An ellipsis is inserted in the body or at the end of a quotation where words have been omitted.
In creative writing, ellipses are frequently used to suggest that a speaker could go on to say more about a specific subject but chooses not to do so. The ellipsis may also suggest an incomplete thought or observation.
To suggest that an ellipsis is required, the proofreader uses an upward-pointing caret to indicate the place where the ellipsis should be inserted and draws an ellipsis ( ... ) in the right-hand margin of the page.
"The Blue Book of Grammar and Punctuation," by Jane Straus, provides extensive guidance concerning the use of the colon. Straus advises use of the colon after a complete sentence that introduces a list of items; instead of a semicolon between two sentences when the second sentence explains or illustrates the first sentence and no coordinating conjunction is used; and "to introduce a direct quotation that is more than three lines in length."
To suggest the use of a colon, a proofreader draws an upward-pointing caret beneath the suggested point of insertion and places a colon ( : ) inside the caret.
A semicolon is inserted between two complete sentences when the clauses are closely related and no conjunction connects them or in lists in which commas are not sufficient to separate the various elements. They function as strong commas or diminished periods.
A proofreader indicates the need for a semicolon by drawing an upside-down caret beneath the suggested point of insertion and placing a semicolon ( ; ) inside the caret.
A question mark is the form of punctuation that marks the end of an interrogatory sentence---that is, a sentence that asks a question.
To recommend the use of a question mark instead of the existing period, the proofreader draws a circle around the period and from the circle a line with a loop to suggest removal of the period; draws an upward-pointing caret to indicate an addition is required; and places a question mark ( ? ) in the right-hand margin.
An exclamation point---or exclamation mark---is used after a word or sentence to convey surprise, strong emotion or determination.
To recommend the use of an exclamation point, the proofreader draws an upward-pointing caret beneath the suggested point of insertion and places an exclamation point ( ! ) inside the caret.