Page 486
Semicolon
A semicolon is a cross between a period and a comma. It sometimes serves as a stopping point (a period), and other times, as a pause (a comma).
486.1 To Join Two Independent Clauses
A semicolon is used to join two independent clauses that are not connected with a coordinating conjunction. (Independent clauses can stand alone as separate sentences.)
I’ll admit it; I’m a bit of a gear-headed gadget freak.
See 528.4 for an explanation and examples of independent clauses.
486.2 To Set Off Two Independent Clauses
Use a semicolon to separate independent clauses if they are long or if they already contain commas.