Punctuation Overview

Periods: full stop

Semicolons: rolling stop

Periods: Periods signals readers to come to a full stop before continuing.

Semicolons: Semicolons signal readers to come to a rolling stop, telling them that a connected idea is coming. Because they link independent clauses, we can think of them as “semi=periods.”

One exception: Use semicolons to separate elements in a series that contains commas or other punctuation within them.

Semicolons must precede conjunctive adverbs that appear between independent clauses; follow the conjunctive adverbs with a comma. Some conjunctive adverbs are however, furthermore, nevertheless, moreover, consequently, etc .

E.g., The following issues are not covered under Quirk Support; however, technicians may provide limited recommendations for these types of issues.

Commas: Slow down

Commas: Commas signal readers to slow down and then speed up again. In professional communication, commas by themselves are not used to join two independent clauses. To avoid a comma splice between independent clauses, use a conjunction or a relative pronoun, or a semicolon, colon, em-dash, or parentheses.

Use commas in pairs to separate:

• A state from a city: e.g., In Seattle, WA, it rains a lot.
• A company from its title: e.g., Entellizon, Inc., paid dividends.
• A date from the year: e.g., The January 5, 1996, memo documented the case.

But remember to set off nonrestrictive modifiers with commas (remember the which/that controversy)

Use a comma before the last item in a series.

Correct comma use with common abbreviations:

e.g., (“for example”): This text contains nominalizations: e.g., recommendation, correspondence, summarization.

i.e., ( “that is” or “in other words”): Nominalization (i.e., nouns make from verbs) are hard to read.

et al.: Jones et al. (1985) found a black hole.

Colons: Colons signal readers to stop briefly and prepare for an elaboration on the initial concept (for example, a definition, a list, an example, etc.). Usually an independent clause precedes a colon while any syntactic structure can follow a colon.

Em-dash: Em-dashes alert readers to step on the brakes and get ready for something unexpected. They are a potent form of punctuation and should be used sparingly. Type them with a long em-dash (—) or with two hyphens with no spaces around them. (Windows keyboard shortcut: Alt+Ctrl+Num- )