The semicolon connects two closely-related sentences. It provides a pause more emphatic than a comma, but less than a period.
Use a semicolon:
- To connect two independent clauses not joined by a coordinating conjunction (for, and, nor, but, or, yet, so).
- Both clauses must be complete sentences.
- Example: Jim walked into the kitchen; the teapot was singing.
- To connect two independent clauses linked with a transitional expression.
- Transitional expressions are words such as accordingly, consequently, instead, nevertheless, however, or similarly, or phrases such as in addition, as a result, in fact, or on the other hand. They are not the aforementioned coordinating conjunctions.
- Example: Jim saw a llama in the kitchen; therefore, he went back into the living room.
- Note that the transitional expression "therefore" is followed by a comma.
- To separate elements in series containing internal punctuation.
- Normally commas separate elements in a series or list, but it can be confusing if the listed items also contain punctuation; a semicolon alleviates this problem.
- Example: Jim had planned to make chocolate, vanilla and carrot cakes; apple, blueberry, and pumpkin pies; and cinnamon, raisin, and oatmeal cookies.
- If commas were substituted for semicolons the reader would have a difficult time determining which words were meant as adjectives (chocolate, apple, raisin) and which were meant as nouns (cakes, pies, cookies). The use of semicolons avoids this.
Do not use a semicolon:
- To join a sentence fragment to a sentence.
- The clauses on each side of a semicolon must be complete sentences.
- Between a subordinate clause and the rest of the sentence.
- A subordinate clause is a complete sentence that contains a subordinating word such as because, rather than, unless, or while. A subordinate clause can be preceded by a comma, but not a semicolon.
- To introduce a list.
- Use a colon for this.
- Between independent clauses joined by a coordinating conjunction.
- This just isn't allowed.