A colon is that punctuation mark which is used for three grammatical purposes.
Those three purposes are:
1. To introduce a list
2. To explain the first clause
3. To use before a quotation
1. Colon Is Used To Introduce a List
You can use a it to introduce a list. For example,
• I think you have three things in your pocket: a pen, a small diary, and a mobile phone.
• Please bring five things from market: vegetables, fruits, yogurt, milk, bread, and eggs.
You see in the above examples that colons are used after the independent clauses. For instance, in the first example, ‘… a pen, a small diary, and a mobile phone’ is a dependent clause. You should be careful in using it. Always place a colon after the clause. This is the rule!
2. To Explain the First Clause
One of the three grammatical uses is that it is used in between the two main clauses. In this way, the second clause explains the first clause. By using this, a writer can explain his thought intensely. For example,
• I know I am done with my work: just to live an exciting life.
• Hundreds days in Switzerland: unforgettable time of my life.
3. Colon Is Used Before a Quotation
A colon is also used before a quotation or a direct speech. For example,
• She said: “Arrive early if you really want a big slice of the chocolate cake.”
• The boss ordered: “I want all the files ready just after two hours.”
Other Uses
Apart from the grammatical uses of a colon, there are also a few non-grammatical uses of a colon. For instance, in ratios, titles, time, references, etc. Let me briefly explain few of them.
1. The colon is used in writing time, for instance, to separate minutes from hours.
9:30 p.m.
11:00 a.m.
2. The colon is used in stating references like biblical references. It is used to separate chapters from verses.
• Genesis 1:27
• Genesis 1:26
3. The colons are used in stating the ratios as well.
1:2
4:3
4. You can find out colons used in formal letters as well.
• Respected Ma’am Madonna:
• To whom it may concern:
Note: Don’t use semicolon after a salutation.
5. Separation of titles and subtitles can be done by using a colon.
• Aphorism: The Girl that is a Beauty
• Intraseasonal Variability: Processes, Predictability and Prospects for Prediction
Remember a Few Rules
Only capitalize the first word after a colon when the first word is a proper noun or there is an independent clause. For example,
• I have only two best friends: Amelia and Leo.
• Forget everything: Be happy!
Sometimes, writers do use a colon before a list and just after a preposition or a verb or the words like including. This is not grammatically correct. You should avoid using a colon in this case. For example,
• The dress that I want should be: pretty, cool, and cheap. (Incorrect)
• There are many good things in this shop such as: laptops, video games, mobile phones, digital cameras, etc. (Incorrect)
In the first example, there is no need to place it. The sentence will be grammatically correct without any punctuation mark. The same case is with the second example.
Check Out: What Is a Comma Splice?
What Did You Learn?
A colon is a punctuation mark that has mainly three grammatical uses and a few non-grammatical uses as well. It is used after an independent clause to introduce a list, to explain, or to use before a quotation.