The semicolon functions halfway between the comma and the period as an indication of a pause. It is stronger than the comma and weaker then the period.
To Separate Independent Clauses
The most common use of the semicolon is to divide the clauses of a compound sentence that are not joined by a word such as and, or or.
The cat stood in the window; he was watching the birds in the bird feeder.
Kasper did not like dogs; nevertheless, he tolerated my mother's cocker spaniel.
To Separate Major Word Groupings from Lesser Ones
Too many commas in a sentence may lead to confusion. The semicolon, as a stronger mark, is therefore necessary to clarify the sentence and make it easier to read.
The young lady, angry, and disappointed after a long day of searching for a letter in cupboards, drawers, closets and boxes, finally collapsed into a heap; and it was a long time before she could be encouraged to look again. [The semicolon separates the compound sentence and clarifies the individual clauses.]
He test drove several white, green, blue and red trucks; several automatics, standards, and four wheel drives; and could not make up his mind which one he liked the best. [The three major divisions, the first two of which contain a number of commas, are clarified by the use of the semicolon.]
