A semicolon is a stronger pause than a comma and a weaker pause than a period. A semicolon usually buffers two chunks of equal grammatical weight such as: items in a complicated list, comparable clauses, or phrases.
***independent clause; independent clause closely related in thought*** (my least understood instance) Often you don't need conjunctions such as but, and, and so with a semicolon.
If you forgo the use of a semicolon and use a comma between independent clauses causes a run-on sentence and is called a comma splice:
A semicolon fixes that problem nicely:
I frequently run red lights; yellow lights never indicate how long I have before red. (Too bad semicolons do nothing for the light situation.)
***When NOT to use a semicolon***
Don't use a semicolon to precede a quotation; use a comma.
Wasn't it Caesar who said; "Et tu Brutae?" (wrong)
Wasn't it Caesar who said, "Et tu Brutae?" (right)
Don't use semicolons between unequal items such as an independent clause/prepositional phrase.
Don't use a semicolon when hooking up a dependent clause/independent clause.
Don't use semicolons to introduce the list.
I have to go buy; bleach, trash bags, a shovel, and something to remove blood from the floor. (wrong on both levels)
I have to go buy: bleach, trash bags, a shovel, and something to remove blood from the floor. (still a bad idea but the grammar is correct)
Now I have to go through my stinking manuscripts and change everything. Thanks, Scott Foresman. I should have memorized you earlier.
I used the Scott Foresman Handbook for Writers by Maxine Hairston and John J. Ruszkiewicz