The colon is a punctuation mark that is indicated by two equally sized dots in a vertical line, that is, (:). Its use in writing helps in formally or emphatically introducing a list, appositives, quotations, or even series. A colon implies a promise and the promise is delivered by the matter following the promise. In this article, we will discuss the appropriate usage of a colon in a sentence according to the rules of English grammar. Appropriate Usage To place extra emphasis or to imply a degree of formality, a colon can be used. The phrase, word, or clause can be used as an apposition to a substantive in the introductory statement. EXAMPLES Word The most important thing for the body to survive: oxygen. Phrase The evil step-mother's intentions were clear: death of the princess. Clause Always keep one thing in mind: never drink and drive. It is included after an introductory statement that indicates a point clearly. EXAMPLES In a List The children asked for many expensive gifts this Christmas: a remote-controlled car, PlayStation 2, the new edition sports shoes, and a Chocolate Labrador. In case of writing a formal, long, or paragraphed quoted passage, a colon helps in separating the introductory statement from the quotation. EXAMPLES For Quotations The golden rule for handling men by Mae West: "Tell the pretty one's they're smart and tell the smart one's they're pretty." Many people are confused about the correct use of a colon in letter writing. In a formal or business letter, the colon is placed after the salutation. In case of an informal letter, a comma follows the salutation. EXAMPLES In Formal/Business Letter

1. Dear Mr. Brown:
2. Gentlemen:
3. To The Chairman:

A colon is used to separate the title from its subtitle. EXAMPLES To Separate Titles

1. Joey Goes to Oberland: Audrey Wins the Trick and Dora of the Lower Fifth by Josephine M. Bettany
2. Imaginary Realist: The Life of Timothy Eugene by Milton Sharp

Incorrect Usage One cannot use the colon to separate the verb from the object. EXAMPLES Incorrect My favorite hobbies are: drawing, painting, sketching, and coloring. Correct My favorite hobbies are drawing, painting, sketching and coloring. The colon in a sentence should not separate the preposition from the object. EXAMPLES Incorrect She was the head of: accounts, cash registers, treasury department, etc. Correct She was the head of accounts, cash registers, treasury department, etc. A sentence that has introduced a word, phrase, or clause by a colon, should end with the introduced element. EXAMPLES Incorrect There were 3 demands of the demonstrators: higher pay rise, longer breaks, and half day on Saturdays, but none of their demands were met by the management. Correct There were 3 demands of the demonstrators: higher pay rise, longer breaks and half day on Saturdays. Unfortunately, none of their demands were met by the management. A colon is also used to indicate time (10:45 am), cite a Biblical passage (John III:14 - 16), introducing a speech in a dialog, and in many more instances.