Read THE PARENTHESIS of Punctuation‚ A Primer of Information about the Marks of Punctuation, free online book, by Frederick W. Hamilton, on

The parenthesis, commonly used in pairs, encloses expressions which have no essential connection with the rest of the sentence, but are important to its full comprehension. It is liable to be neglected by writers because the dash is easier to make, and by printers because it is generally thought to mar the beauty of the line. Its distinct uses, however, should not be neglected.

Rules for the Use of the Parenthesis

1. To introduce into a sentence matter which is not essentially connected with the rest of the sentence, but aids in making it clear.

Trouble began when the apprentice (who had been strictly forbidden to do so) undertook to do some work on his own account.

This year (1914) saw the outbreak of a general war.

2. In reports of speeches to enclose the name of a person who has been referred to, or to indicate expressions on the part of the audience.

The honorable gentleman who has just spoken (Mr. Lodge) has no superior on this floor in his knowledge of international law. (Applause.)

3. Parentheses enclosing interrogation points or exclamation points are sometimes introduced into a sentence to cast doubt on a statement or to express surprise or contempt.

He said that on the fifth of January (?) he was in New York.

This most excellent (!) gentleman.

4. Parentheses are used, generally in pairs, sometimes singly, to enclose the reference letters or figures used to mark division and classification in arguments or in precise statements.

This is done because: (a) it is clearer; (b) it is shorter.

These signs may be printed in several ways.

(a) a) (^a) ^a) (1) 1) (^1) ^1)

The old-fashioned form of parenthesis, always made too thin, may need a thin space between it and its adjoining character when it is placed too close to any letter that nearly fills the body in height, as in ( Hall ). The space may not be needed when the proximate character has a shoulder, as in ( Art), or when the parenthesis follows a period.)

The italic form of parenthesis is objectionable in book work. Distinction is sought for the word in italic and not for the parenthesis enclosing the word. The italic parenthesis may be used in job-work or full display lines of italic letters.