A semicolon sits half way between a full stop and a comma. It is used instead of a full stop when we want to avoid too strong a break between the sentences and instead of a comma when we need a stronger break.
Semicolons are also used in place of commas in lists that contain commas.
According to our records your son missed school on Monday, May 2nd; Thursday, May 5th; and Friday, May 6th.
When punctuating a series of phrases containing a comma, you should use semicolons instead of commas to separate the phrases from one another.
Henry's mother believes three things: that every situation, no matter how grim, will be happily resolved; that no one knows more about human nature than she; and that Henry, who is thirty-five years old, will never be able to do his own laundry.
Semicolons can be used before conjunctions like therefore, however when joining two sentences. In this case the connector must be followed by a comma.
I’m 100% positive I didn’t make any mistakes in my report; however, I’m willing to proofread it once more.
Do Not
Do not link a dependent clause or a phrase to an independent clause by way of a semicolon.
Although achieving good results with this method is possible (dependent clause); reasearch shows it is unlikely. (independent clause)
dependent clause + comma + independent clause
Although achieving good results with this method is possible, research shows it is unlikely.
Do not place a semicolon before a conjunction (but, as, etc. )that links two independent clauses, unless the two independent clauses are very long and already contain a number of commas.
I have been waiting a long time for my divorce to come through; but now I wish I never asked for it.
independent clause + comma + conjunction + independent clause
I have been waiting a long time for my divorce to come through; but now I wish I never asked for it.
Rule of Thumb
As a general rule of thumb you should use a semicolon only where a full stop (or period) could also go well.
See also
Punctuation
