It is not uncommon to see commas, semicolons, and periods confused when it comes to joining two independent clauses for forceful and effective writing. Make your writing more powerful by understanding the proper use of the semicolon.
An independent clause contains a subject and verb, and conveys a complete thought. It is a sentence in its own right.
When joining two independent clauses without the use of a coordinating conjunction (and, but, or, or nor), use a semicolon.
- I went to the market; I forgot to buy milk.
Or treat the clauses as separate sentences.
- I went to the market. I forgot to buy milk.
Do not use a comma in the absence of a coordinating conjunction.
- Wrong: I went to the market, I forgot to buy milk.
Overuse of small sentences can affect the flow of your writing, resulting in Dick and Jane grade school primer-type text. The use of semicolons can help eliminate this and can align sentence content more closely. However, semicolons should be used sensibly. Be sure that the independent clauses involved are directly related, and take into account the balance of the clauses in terms of length and import; otherwise treat them as separate sentences.
- No: Thank you for your letter of May 12; we are updating your contact information and you should receive a revised contract within three business days.
- Yes: Thank you for your letter of May 12. We are updating your contact information and you should receive a revised contract within three business days.
Sources: The Gregg Reference Manual; Fumblerules by William Safire; the Internet