The semi-colon is somewhere in between the full stop and the comma; it separates more than the comma but not as much as the full stop. Let’s look at the different places it is usually used to get a better idea of what this means.
The semi-colon is used to:
One use of semi-colons is to separate two independent clauses. For example:
It is looking very sunny out; I think I will wear a t-shirt.
Here we have the independent clause ‘It is looking very sunny out’ linked to the other independent clause ‘I think I will wear a t-shirt.’ This could also be written with a full stop instead of a semi-colon, as in:
It is looking very sunny out. I think I will wear a t-shirt.
This example seems much more abrupt than the previous example with the semi-colon. This is a good thing if that is what one is trying to express; however, it is bad if one is looking for a more flowing sentence. These two independent clauses are very much linked, and they are also both quite short – both of which might influence the use of the semi-colon. This doesn’t make either strictly right; it depends on the aim of the writer. One thing it is probably best to avoid here is to use a comma to separate these two independent conjunctions, as in:
It is looking very sunny out, I think I will wear a t-shirt.
This would be comma splicing, which is generally frowned upon.
2) To separate words, phrases or clauses which have parenthetical constructions attached to them
Semi-colons can also be useful when we have a series of words, phrases or clauses which have parenthetical constructions attached to them. This is because these parenthetical constructions need commas around them, and when we combine the commas of the series with the commas of the parenthetical constructions it can get messy and difficult to follow. For example:
John Smith, the man who everyone hated, Jane Watson, the only person who didn’t hate John Smith, George Saunders, a militant atheist, Ben Davis, a man of the church, and Amy Saunders, the new girl in town, all sat in a room looking at each other.
We could add semi-colons before moving on to the next person in this example, in an attempt to make it clearer, as in:
John Smith, the man who everyone hated; Jane Watson, the only person who didn’t hate John Smith; George Saunders, a militant atheist; Ben Davis, a man of the church, and Amy Saunders, the new girl in town, all sat in a room looking at each other.
3) To set off a conjunctive adverb, or prepositional phrase, joining two independent clauses
There is also the option to use a semi colon to set off a conjunctive adverb (e.g., consequently, finally, furthermore, moreover, however, nevertheless, therefore) joining two independent clauses. For example:
John’s handwriting is very messy; consequently, he is even more stressed during exams than everyone else.
Here the independent clause ‘John’s handwriting is very messy’ is linked to the other independent clause ‘he is even more stressed during exams than everyone else’ by the conjunctive adverb ‘consequently.’ Note the semi-colon at the end of the first independent clause, after ‘messy’, and the comma after the conjunctive adverb ‘consequently.’
If the conjunctive adverb were at the end, we would still see the semi-colon at the point between the two independent clauses, but the comma would be before the conjunctive adverb ‘consequently,’ as in:
John’s handwriting is very messy; he is even more stressed during exams than everyone else, consequently.
Likewise, if the conjunctive adverb is in the middle of the second clause, we will still have the semi-colon in between the two clauses, but the conjunctive adverb will be surrounded by commas, as in:
John’s handwriting is very messy; he, consequently, is even more stressed during exams than everyone else.
Prepositional phrases like ‘in addition,’ ‘for example’ and ‘in contrast’ can also be used with a similar function. For example:
Jane had many problems to think about; for example, she needed to get a new job and find a new flat in just one months time.
Mixing up conjunctive adverbs with coordinating and subordinating conjunctions
It can be easy to mix up the aforementioned conjunctive adverbs with co-ordinating conjunctions and subordinating conjunctions.
We don’t usually use a semi-colon for linking to subordinate/dependent clauses, via subordinating conjunctions, as in:
I had got all the way to work before I realised I had left my front door open.
Here we he have the independent/main clause ‘I had got all the way to work’ linking to the dependent/subordinate clause ‘before I realised I had left my front door open’ via the subordinating conjunction ‘before.’ We don’t need a semi-colon here because the two clauses are too dependent on each other.
In contrast, there are some circumstances where two independent clauses being linked by a co-ordinating conjunction could be used. These might be because the sentence is particularly complex and messy because of an abundance of parenthetical elements and commas, as in:
I read a whole, though admittedly short, novel, last night, from start to finish; but I can’t remember, to my complete shame, a single interesting thing about it.
Here we have the coordinating conjunction ‘but’ linking two complex independent clauses which have a lot of commas due to parenthetical elements. Now look at it without the semi-colon:
I read a whole, though admittedly short, novel, last night, from start to finish, but I can’t remember, to my complete shame, a single interesting thing about it.
The difference is subtle here, as it often is with the semi-colon, but the extra separation in the first example could be said to help make it a little clearer.
Next, let’s look at the colon.
NEXT: 6) The colon