Science, Technology and Engineering

Academic Language and Learning

Semi colons (;)

For its most common use it may be helpful to think of the semi colon as a full stop: what comes before the semi colon and what comes after are, in fact, sentences. The word following a semi colon does not have a capital letter (unless it would otherwise require one).

Major Uses

To separate ideas that are of equal grammatical weight and value (main clauses)

Elephants are associated with memory; lions are associated with majesty.

 

In extroverts inhibition is weak and excitation strong; in introverts the opposite is true.

NB: It would be correct to write each of these examples as two sentences, replacing the semi colon with a full stop. It would also be correct to join the ideas in each sentence with a conjunction, or joining word, such as and; however, it would be incorrect to join them with commas alone.

To separate items where commas have already been used

She found many pieces of equipment left in his private laboratory: his notebook, with the results of all his experiments; the remains of his last robot, which had failed miserably; and two bunsen burners.

Before clauses beginning with certain adverbs (adverbial conjunctions) such as so, therefore and however

A knowledge of animal behaviour can contribute to effective management; therefore it is important to include the subject in any agricultural science degree.

To separate lists of authors

Many later experiments found similar results (McDonald, 1992; Pearson et al., 1989; Walsh, 1995).