# Semicolons and colons - Graduate Writing Center

Nested Applications

## Semicolons and Colons

A semicolon is not, as it turns out, half a colon; but, as their names imply, semicolons and colons are in some ways closely related—and quite distinct in others.

Both can be used to join independent clauses, with somewhat subtle distinctions in effect. Both are also involved in the construction of lists, though they play different—and complementary—roles.

### Semicolons

1. Semicolons can connect independent clauses; use of a semicolon indicates a close conceptual relation between discrete ideas:

Jean Cras orchestrated Polyphème while captaining a torpedo boat during the Adriatic Campaign of WWI; it was to be his only opera.

Semicolons therefore overlap in function with coordinating conjunctions; the effect, however, is different:

Semicolons therefore overlap in function with coordinating conjunctions, but the effect is different.

Note that a semicolon (or colon) is required when joining two independent clauses without using a conjunction, even when a conjunctive adverb is present; joining independent clauses with a comma alone is an error called a comma splice:

Yes: The international system is, in the end, anarchic: there is no overriding authority capable of arbitrating conflicts between states.

No: The international system is, in the end, anarchic, there is no overriding authority capable of arbitrating conflicts between states.

Yes: The international system is, in the end, anarchic; however, institutions can incentivize cooperation among states.

No: The international system is, in the end, anarchic, however, institutions can incentivize cooperation among states.

Just remember: a comma splice will not suffice.

(Opinions differ on whether it is acceptable to place a coordinating conjunction after a semicolon; so it’s up to you whether it’s worth risking stylistic censure in service of rhetorical effect.)

1. When a list is made up of items that themselves contain commas, semicolons clarify the list structure:

U.S. capitol cities include Sacramento, California; Lansing, Michigan; and Carson City, Nevada.

Without the semicolons, the boundaries between list items are muddier:

U.S. capitol cities include Sacramento, California, Lansing, Michigan, and Carson City, Nevada.

1. Semicolons separate multiple attributions in a single citation:

(Roussel 1912; Rimsky-Korsakov 1888)

### Colons

The colon is a punctuation mark that says, in essence, “and here it is”: it announces that something just discussed is about to appear or be restated or further explained.

The relationship between the information on either side of the colon is therefore different from that created by a semicolon: while the semicolon indicates close relation, the colon generally signals identity.

1. Like the semicolon, the colon can join independent clauses, indicating reiteration or further development of a given idea:

Launch conditions were far from ideal: high wind speeds sent the balloon off course by 15 km, thereby compromising data collection.

A semicolon here would be technically acceptable but less conceptually precise: the statement that follows the colon defines the aforementioned adverse conditions rather than introducing a separate but related idea. Compare this sentence:

Launch conditions were far from ideal; further trials were therefore necessary to collect the required data.

1. Colons introduce lists, appositives (renaming / specification), and quotations:
• The remainder of this thesis is organized as follows: Chapter II provides . . . ; Chapter III describes . . . ; Chapter IV . . . .
• In this case, however, one instrument of national power overshadows the others: economics.
• Sun Tzu said it best: "Don't believe everything you read on the internet."

When using the colon in this way, be sure the introductory statement is a complete independent clause; that is, do not insert a colon where it will create an incomplete clause:

Yes: The DIME paradigm comprises diplomacy, information, military, and economics.

No: The DIME paradigm comprises: diplomacy, information, military, and economics.

Here, “comprises” needs an object(s), so cutting off the syntax with a colon separates sentence components that need to be grouped together in the clause.

1. Finally, colons perform assorted functions in constructions related to time, mathematics, and citation styles.

GWC - all topics list heading

### Writing Topics A–Z

This index makes findings topics easy and links to the most relevant page for each item. Please email us at writingcenter@nps.edu if we're missing something!

## A

 abbreviations abstracts academic writing acronyms active voice adjectives, compound advisor, selecting and working with AI apostrophes appointment with GWC coaches, how to schedule argument article usage artificial intelligence assignments, understanding them audience return to top ↑

## B

 body paragraphs booking an appointment with a GWC coach brackets, square brainstorming return to top ↑

## C

 capitalization citations charts ChatGPT citation software citation styles clauses clarity clustering coaching, about coaching, how to schedule colons comma splices commas, FANBOYS commas, introductory commas, list commas, nonessential / nonrestrictive information commas, Oxford commas, serial common knowledge commonly confused words compare-and-contrast papers compound adjectives / modifiers concision conclusions conference presentations conjunctive adverbs coordinating conjunctions copyright and fair use critical thinking return to top ↑

## D

 dangling modifiers dashes dependent clauses dependent marker words display equations distance learning double submission of coursework drafting Dudley Knox Library return to top ↑

## E

 editing your own work editing: outside editors em dash en dash equations exclamation points executive summary return to top ↑

## F

 FANBOYS FAQs figures first person, use of in academic writing footnotes fragments free-writing return to top ↑

## G

 generative artificial intelligence (AI) gerunds grammar graphics graphs group writing GWC appointment, how to schedule return to top ↑

## H

 homophones Honor Code, NPS human subjects research hyphens return to top ↑

## I

 ibid. incomplete sentences independent clauses Institutional Review Board interviews, conducting introductions IRB iThenticate return to top ↑

## L

 LaTeX library liaisons lists, syntax of literature reviews logic and analysis return to top ↑

## M

 M dash making a GWC appointment mathematics memos methodology modifiers, compound modifiers, misplaced return to top ↑

## P

 paragraph development parallelism paraphrasing parentheses parts of speech passive voice periods persuasion phrases vs. clauses plagiarism, how to avoid plagiarism-detection software plain language polishing prepositional phrases prepositions pronouns, clarity with pronouns, grammar of proofreading publishing punctuation return to top ↑

## R

 Reading with Intent I Reading with Intent II redundancies reference software reflection papers research research guides, discipline-specific research questions restrictive vs. nonrestrictive information reusing papers reverse outlining revision roadmaps run-on sentences return to top ↑

## S

 scheduling a GWC appointment self-citing semicolons sentence fragments serial comma signal phrases significance so what? source blending sources, engaging with / critiquing sources, evaluating the reliability of sources, citing spelling standard essay structure STEM / technical writing Strategic Reading I Strategic Reading II style subject–verb agreement subjects, grammatical subordinating conjunctions summarizing surveys, administering return to top ↑

## T

 tables teams, writing in technical writing tense that vs. which thesis advisor, selecting and working with thesis process overview Thesis Processing Office (TPO) thesis proposals: common elements thesis statements thesis writing this, that, these, those tone, professional topic sentences transitions types of papers return to top ↑