The semicolon (;) is regularly a strong comma or a weak period.
1) The semicolon is used between two main clauses not joined by one of the simple co-ordinating conjunctions – ‘and’. ‘but’. ‘or’. ‘nor’. ‘for’.
- Property can be paid for the lives of peaceful and innocent people cannot be.
- The semicolon is a much stronger mark of separation than the comma; it is almost as strong as the period.”
- “With educated people, I suppose, punctuation is a matter of rule; with me it is a matter of rule; with me it is a matter of feeling. But I must say I have a great respect for the semicolon; it’s a useful little chap.”
2) Conjunctive Adverbs (such as, accordingly, also, anyhow, besides, consequently, furthermore, hence, thus, however, indeed, instead, likewise moreover, nevertheless, so, still, then, therefore) are not simple co-ordinating conjunctions. Thus in accordance with the rule, main clauses joined by these adverbs should be separated by the semicolon.
- He did his classwork well; therefore, he had no problems during the examination.
- Caesar was dead; hence, Rome was in confusion.
3) Explanatory expressions (such as for example, infact, namely, on the contrary, on the other hand, that is) are similar in use to confunctive adverbs; that is, main clauses joined by them must be separated by the semicolon.
- He is coming today; in fact, he is due here now.
4) Use the semicolon to separate two or more co-ordinating elements which themselves contain commas.
- The Lake is useful as a source of electrical energy, pouring its waters through the mighty turbiness; as a reservoir, holding back the floods from the swollen rivers; and as a place of recreation, providing bathing, boating, and fishing.
5)Caution: Do not use the semicolon between parts of unequal rank, such as a clause and a phrase or a main clause and a subordinate clause.
WRONG: Benson is now in good health; although he has been an invalid most of his life.
RIGHT: Benson is now in good health, although he has been an invalid most of his life.