A semicolon is used as a substitute for a period or a comma in specific situations:
- to join main clauses that are of equal importance, have a close relation, and are not linked by a coordinating conjunction (and, but, or, nor, for, yet, so), unless the clauses are long, complex, or have internal punctuation.
Please wait for me; don't go anywhere.
- to join main clauses linked by conjunctive adjectives (consequently, for instance, furthermore, hence, however, indeed, moreover, nevertheless, subsequently, therefore, thus)
I wanted to graduate this this year; however, I will not complete all of the required courses until next year.
- to separate items in a series, if the items in the series are long or include commas
Elves are known to gather nuts, berries, and potatoes; to hoard large amounts of gold; and to rob people of food, drink, and even children.