1. A semi-colon (‘;’) is used between two independent clauses (i.e. two complete mini-sentences) when they are so closely related in meaning that they feel as if they
should be a single sentence.
Example: The desert was a sea of endless sand; not a plant to be seen.
2. A semi colon is used to join two independent clauses (simple sentences) where the conjunction has been left out.
The following sentence has used a conjunction (or a joining word) to combine two simple sentences together.
Example: The forest was wet and dark, and the vegetation thick and dense.
This sentence could also be written replacing the conjunction with a semi colon, but only when the sentences are closely related.
Example:The forest was wet and dark; the vegetation thick and dense.
3. A semi colon is used to prevent confusion in sentences (especially complex lists) where commas would confuse the reader.
A complex list of sentences, rather than single words, are often separated with semi-colons (‘;’) instead of commas to help keep the list clear.
This usually includes a semi-colon before the final ‘and’.
Example: York and Latham; Butch Cassidy and the Sundance Kid; and Bonnie and Clyde are infamous American partners in crime.
4. Use a semicolon between two sentences joined by a coordinating conjunction when one or more commas appear in the first sentence.
Example: When I finish here, I will be glad to help you; and that is a promise I will keep.
Example: If she can, she will attempt that feat; and if her husband is able, he will be there to see her.