The easiest way to approach the use of the semicolon is to first examine some uses of the comma. Commas are used between items in a series:
"Hup, two, three, four!" barked the sergeant.
Commas are also used between the independent clauses of compound sentences.
I tried to call you, but I got your answering machine.[Clauses are constituents of a sentence containing a subject and a predicate. If the clause expresses a complete thought and can stand by itself as a complete sentence, it is said to be a main or independent clause. Two or more independent clauses joined by a coordinating conjunction, such as and or or, form a compound sentence.]
In the examples above, commas maintain continuity by indicating that more is to follow. Commas thus simultaneously join elements and separate them from one another. Semicolons do this as well, but they signal more significant breaks in the sentence than commas do. This will become clearer as we examine the principal uses of the semicolon.
Series of items themselves containing commas
Semicolons, not commas, are used between items in a series when these items themselves contain commas:
Mary-Margaret was wanted for drunk and disorderly in Death Valley, California; Tombstone, Arizona; and Truth or Consequences, New Mexico.
Clauses containing commas
Semicolons, not commas, are used between independent clauses when the clauses themselves contain commas:
After squandering uncounted billions of dollars to prop up a corrupt and despotic regime, we find ourselves no closer to putting down the insurgency; yet my colleague, the distinguished senator from Mississippi, would have us, against the dictates both of common sense and of common decency, continue to pursue the foredoomed policies of his party.These examples raise the question of style. Senator-bashing favors the long, formal sentences where semicolons are most at home; doctor's orders do not. There is no shame in a well-placed period. Perhaps the doctor should have revised a bit:Take aspirin, drink lots of fluids, and get plenty of rest; but be sure to call me if your temperature goes above 102.
Take aspirin, drink lots of fluids, and get plenty of rest. Be sure to call me if your temperature goes above 102.
Independent clauses joined by conjunctive adverbs
Semicolons are used between independent clauses joined by conjunctive adverbs, such as however, moreover, consequently, thus, instead, and nevertheless:
The auditor's final report will not be available until August; however, this should not preclude our immediately implementing certain recommendations.
Independent clauses not joined by conjunctions
Semicolons are used between the independent clauses of compound sentences in the absence of a coordinating conjunction, such as and, but, or, nor, for, or yet:
Few soldiers were as courageous; none was so kind.A period or a coordinating conjunction could have been used instead of a semicolon, or a semicolon and a conjunctive adverb could have been used together:
Few soldiers were as courageous. None was so kind.Here the choice of punctuation is a matter of accommodating style to sense. Unlike the period, the semicolon connects the clauses that it separates. Unlike the conjunction and adverb, which may make all too explicit the relationship between clauses, the semicolon calls upon the reader to appreciate the equilibrium, contrast, or alternation implicit between closely related clauses.
Few soldiers were as courageous, and none was so kind.
Few soldiers were as courageous; moreover, none was so kind.