Definition: a punctuation mark (;) indicating a pause, typically between two main clauses, that is more pronounced than that indicated by a comma.
Note: Do not rely on grammar or spelling checkers to identify missing or misused punctuation. Although a checker may flag possibly missing or incorrect marks, it cannot do much else. While I still recommend using these AI checkers while you’re writing, I insist that you also trust a qualified human being to copyedit any work that you are working toward publishing.
A semicolon is essentially a weak period. It resides between two full sentences in the same way a period does, but acts as a slightly shorter pause, about as much as a comma. However, not all periods can be replaced with semicolons. Typically, only when there is a direct relation between two sentences should a semicolon be used.
In Place of a Comma and a Conjunction:
If two independent clauses are not connected by and, but, or, nor, for , so, or yet, you canseparate them with a semicolon.
- e.g. Nancy visited for a few days; everyone was glad to see her.
Use a semicolon before an independent clause introduced by hence, therefore, that is, however, then, indeed, for example, namely, etc.
- e.g. Your application is incomplete; therefore, we cannot accept you for the position.
Do not use a semicolon to separate an independent clause from a dependent one.
- e.g. Your application is incomplete, so we cannot accept you for the position.
In a Series:
Semicolons may also be used as a “super comma” in some cases.
Use a semicolon to separate items in a series if any of the items contains a comma. (Note that not all items must have a comma, though all do in this example.)
- e.g. I brought two bathing suits, in case one got dirty; some snacks, so we can eat; and a blanket, to lay out on the sand.
Use a semicolon to separate items in a series if they consist of complete sentences.
- e.g. The teacher told her students three things: Do not bully other students; do not stray from the group; and always try your best.
With Other Punctuation:
A semicolon goes outside of an end quotation mark.
- e.g. Maggie stood to recite “The Raven”; she waited for the audience’s attention.
A semicolon never precedes a parenthesis (unless the parenthesis is used typographically, in mathematics, or as a design feature).
- e.g. Justin was a genius (at least we hoped so); he always had a plan.
For further information, see my other Punctuation articles:
Aaron, J.E. & Morrison, A. The Little, Brown Compact Handbook, 5th Canadian ed. Pearson, 2013, chap 5
Judd, K. Copyediting, A Practical Guide, 3rd ed. California, CA: Crisp Learning, 2001, chap 4