32a Use a semicolon between closely related independent clauses not joined with a coordinating conjunction.

When two independent clauses appear in one sentence, they are usually linked with a comma and a coordinating conjunction (and, but, or, nor, for, so, yet). The coordinating conjunction signals the relation between the clauses. If the relation is clear without a conjunction, a writer may choose to connect the clauses with a semicolon instead.

In film, a low-angle shot makes the subject look powerful; a high-angle shot does just the opposite.

A semicolon must be used whenever a coordinating conjunction has been omitted between independent clauses. To use merely a comma creates a type of run-on sentence known as a comma splice. (See 21.)

An example.