Use a semicolon to join two sentences or to punctuate a series or list of appositives that already includes commas.

The semicolon offers a "higher" form of punctuation than the comma or dash. Unlike commas or dashes, the semicolon can correctly be used to separate sentences. If readers tend to pause for a half-second when they come to a comma, they pause for three-quarters of a second when they reach a semicolon. Writers use semicolons two major ways.

Use a Semicolon to Join Two Sentences

You can show that ideas are closely related by using a semicolon rather than a period between them.

  • The secretary's fingers burned across the typewriter; the financial statements would be picked up by the client in one hour.
  • The question, though, is not economics; it is professional objectivity.
  • Breast cancer used to be the biggest killer for women; now it's lung cancer.

Use a Semicolon to Punctuate a Series or List of Appositives That Already Includes Commas

When elements in a series require internal commas to ensure clarity, then semicolons must be used to separate those elements:

  • A perfect vacation would be long, relaxing, and cheap; include personable, sweet, flexible people; and make everything else seem trivial.
  • The delegates were from Sacramento, California; Jacksonville, Florida; Providence, Rhode Island; and Ann Arbor, Michigan.
  • A good proofreader must have good grammar, punctuation, and spelling skills; must like to read; and must have patience.

Note, however, that you are wise to avoid using unnecessary semicolons. Experienced writers and readers would prefer the second sentence because it avoids self-conscious punctuation.

  • He was dressed in white pants; a white, Mexican wedding shirt; and sandals.
  • He was dressed in a white, Mexican wedding shirt, white pants, and sandals.