The colon is a punctuation mark and is often used as something in between a full stop (period) and a comma. It is often used as a connecting sign as well as indicating that part of a sentence follows on directly from the previous sentence. It can be confusing as to whether a sentence that follows a colon should begin with a capital or not. And why, for example, do we use colons between two sentences instead of a full stop or a semi-colon?

Well, the colon always emphasises the connection of two or more sentences and is often more effective than using either the full stop or the semi-colon. As for most aspects of English grammar, there are set rules for using the colon. The colon is used instead of a full stop or semi-colon between two sentences when the second sentences illustrates or explains something in the first sentence. This is because the second sentence follows as a result of the first. The colon is often used in lists and introduces a logical order. It is also often used when introducing a quotation (which is encased in speech marks and always begins with a capital letter):

She exclaimed: "Oh my goodness!"

The use of capitalization or lower-case after colons often varies depending on whether you are using British or American English. In British English, the word following the colon is kept in lower-case, unless it is a proper noun (a person's name or place name, country etc) or an acronym (AIDS, NATO, JPEG etc). In American English, the word following a colon is sometimes capitalized if it starts a complete sentence rather than a list. However, many writers also use lower-case in the following sentence, so it seems it is becoming a matter of choice and preference. If two or more sentences follow after the colon, then the first word of each sentence should be capitalized.

British English

"There are five rooms in the apartment: two bedrooms, one living room, kitchen and bathroom."

"There are many infectious diseases in the world today: AIDS is but one of them."

"There are many beautiful cities in the world: Copenhagen is one of the loveliest in my opinion."

American English

"The reason for his success: ambition and hard work."

"Salt should be used sparingly in cooking: It can raise blood pressure in some people. Salt can also worsen water retention, which is a problem for many people."

Lists

When you are writing a list after a colon, you do not capitalize the first word unless the word is a proper noun:

"I like lots of types of chocolate: dark, milk, white, fruit and nut."

"I like lots of types of chocolate: Belgian truffles, Swiss truffles, Hershey bars and Lindt chocolates."

KJ Hutchings is the owner of KJ Language Services, providing proofreading, editing and writing services to businesses and students, in particular those who use English as a second language. For more information, visit her site at: http://www.kjlanguageservices.com/