Full stop (Britain) and Period (US) (.)

The period is the most terminal mark of punctuation.

Rule 1:

A period is used at the end of a declarative sentence. For example: We have nothing to fear but fear itself.

Rule 2:

A period is used at the end of an imperative sentence. For example: Go at once. She said, “Help me”.

NOTE: Do not use a period when an imperative sentence is so strong that it becomes an exclamation. Such a sentence is followed by an exclamation mark. Whether an imperative sentence is ended by a period or an exclamation mark depends entirely on the degree of emphasis desired:

  • “Go at once!” he shouted.
  • “Help!” she cried.
Rule 3:

A period is used at the end of a sentence that is interrogative in form but to which an answer is not required. For example:

Children, will you stop that noise at once.

Rule 4:

Periods are used in courtesy titles and abbreviations of rank which appears before a name.For example:

  • Mr. Rakesh
  • Lt. Mohan Singh
  • Dr. Smith
Rule 5:

A period is used to represent a decimal point.

Example: 20.4, 58.5%

Rule 6:

A period is used after figures and letters to represent principal divisions of lists. For example:

  • A. Expenses
  • V. Gross income
  • 1. Net income
  • a. Net earning per share

NOTE: Do not use a period when the figures or letters are in parenthesis such as : (1) Net income

Rule 7:

A period is used with many abbreviations. Such as:

  • M.D.
  • etc.
  • Mon.
  • Jan.
Rule 8:

Use periods for academic degrees when abbreviated. Such as:

  • B.A.
  • Ph.D.

NOTE: Do not use a period with abbreviations that are accepted as the shortened form of proper nouns. Such as:

  • NASA
  • MLA
  • BBC
  • VIP
  • UNO
Rule 9:

The period is placed outside the closing parenthesis when the parenethesis encloses the last word of a sentence. The period is placed inside the closing parenthesis only when what is enclosed in parenthesis is a complete sentence and the first letter is capitalized. Example:

  • This is called the law of natural selection (Darwinism).

It is wrong to write as: This is called the law of natural selection. (This law cannot be too highly stressed in the study of biology.)

Rule 10:

When a sentence ends with an abbreviation that requires a period of its own, no second period is added. For example:

For your first school-day, you must remember to take paper, pencils, erasers,etc.

Rule 11:

A period is used to mark the end of a group of words that is not a full sentence, but which is complete in itself. For example:

  • Over an over.
  • Again and again.
  • Relentlessly.
Rule 12:

Nowadays after Dr, Mr, Mrs, St(Saint) full stop is not used. For example:

  • Dr Hari Prasad
  • Mr (also Mr.)
  • Mrs (also Mrs.)
  • Ms (also Ms.)