A comma is a punctuation mark that represents a short pause and is used to divide parts of a sentence. The purpose of a comma is to indicate to readers a certain separation of words, phrases, or ideas in order to prevent misreading the writers intended meaning. When a sentence is spoken aloud, a comma often represents a pause, which in verbal conversation functions to clarify meaning. The use of the comma can be categorized into eight basic rules:

1. Use a comma to separate independent clauses.
2. Use a comma after an introductory clause or phrase.
3. Use a comma between all items in a series.
4. Use commas to set off nonrestrictive clauses.
5. Use commas to set off appositives.
6. Use commas to set off parenthetical elements.
7. Use commas to set off direct address.
8. Use commas to separate parts of a date or location.

In general, the use of commas allows the reader to be assured of proper interpretation of the writers intentions.