Uses of the semicolon

THE SEMICOLON

Use a semicolon to join/separate closely related, complete sentences.

The semicolon is stronger than a comma, but weaker than a period (full stop). A period separates two independent clauses with complete finality; a semicolon, on the other hand, signals a less final ending and indicates that the following clause will convey an additional idea that is closely related to the current one. Thus, the semicolon tells the reader to expect more information on the same idea, whereas a period signals clear end to the idea just expressed.

Here, the semicolon is typically used to substitute for

ABC will provide an estimate of this cost increase; traditional costing will not.

A comma and a co-ordinating conjunction, such as 'and', 'but', 'or', 'nor', 'so', or 'yet', could be used instead of the semicolon. Thus, the above sentence could also be re-written as any of the following examples.

ABC will provide an estimate of this cost increase, and traditional costing will not.
ABC will provide an estimate of this cost increase, but traditional costing will not.
ABC will provide an estimate of this cost increase, yet traditional costing will not.

Alternatively, the two main clauses could also be separated by a full stop/period and expressed as two separate sentences, with or without a connector.

ABC will provide an estimate of this cost increase. Traditional costing will not.
ABC will provide an estimate of this cost increase. However, traditional costing will not.

Use a semicolon to separate items in a list in cases where one or more of the items contains commas or other punctuation.

Usually, we use a comma to separate three items or more in a list. However, if one or more of these items contain commas, then you should use a semicolon, instead of a comma, to separate the items and avoid potential confusion.

For example, three items, one of which contains an 'internal comma' could be written as a formatted list, as shown below.

Transactions can be scored discriminatingly on three dimensions:

asset specificity
uncertainty (including complexity, which is similar to uncertainty in its effects)
frequency

However, when presented as an unformatted list, these same items would have be separated by semicolons:

Transactions can be scored discriminatingly on three dimensions: (1) asset specificity; (2) uncertainty (including complexity, which is similar to uncertainty in its effects); and (3) frequency.

Use a semicolon before introductory words

A semicolon can also be used between two independent clauses, when the second clause begins with a sentence connector as the introductory element. Generally, the semicolon here could be substituted by a period without any change in meaning.

In the development of the various engineering disciplines in the 19th and 20th centuries, considerable overlap was inevitable among the different fields; for example, chemical engineering and mechanical engineering were both concerned with heat transfer and fluid flow.

however, moreover, therefore, in addition, nevertheless

Similarly, a semicolon can be used before introductory words that are followed by a list of three or more items and preceded by a complete sentence.

namely, that is (i.e.), for example (e.g.), for instance

Use a semicolon to separate references to other authors' work within a single citation in your own text

Use semicolons to refer to several authors' work when using the "author and date" method for citing earlier works within your text. These details appear within brackets (Am. parentheses) in your text (See also non-integral citations/references)

Note: when different studies by the same author are listed, then only a comma is used between the years.

Several authors mention the use of an ABC analysis as a basis for performing a VCA (Guilding et al., 2000; Mecimore and Bell, 1995; Shank and Govindarajan, 1992, 1993).

(Williamson, 1985, 1996; cf. also Mahoney, 1992).