A semicolon has two main jobs: joining two closely related independent clauses (complete sentences) without a conjunction, and separating items in a list where the items themselves contain commas. It's stronger than a comma but softer than a full stop — a way of saying "these two ideas are separate sentences, but closely connected."
Use 1: joining two related complete sentences
Use a semicolon between two complete sentences that are closely related in meaning, instead of starting a new sentence or using "and":
- "I have a big exam tomorrow; I can't go out tonight."
- "The weather was perfect; we decided to walk instead of driving."
The test: could each half stand alone as its own complete sentence? If yes, and they're closely related, a semicolon works. If either half is NOT a complete sentence, you need a comma or nothing at all instead.
Use 2: separating items in a complex list
When list items already contain commas, using more commas between them gets confusing — semicolons make the boundaries clear:
- "We visited Paris, France; Rome, Italy; and Madrid, Spain."
Without semicolons, it's unclear whether this is a list of three cities (each with its country) or six separate places.
What NOT to do
- Don't use a semicolon where a comma is needed, e.g. after an introductory phrase: "Although it was raining; we went outside" should be a comma, not a semicolon (because "Although it was raining" isn't a complete sentence on its own).
- Don't capitalise the word after a semicolon unless it's a proper noun — it's not the start of a brand-new sentence in the traditional sense.
