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The period

Use a period to end all sentences except direct questions or genuine exclamations. Also use periods in abbreviations according to convention.

Reported or indirect question

If a sentence reports a question instead of asking it directly, the sentence should end with a period, not a question mark.

Example sentence with editing. Original sentence: Joelle asked whether the picnic would be canceled? Revised sentence: Joelle asked whether the picnic would be canceled.

Mild exclamation

If a sentence is not a genuine exclamation, it should end with a period, not an exclamation point.

Example sentence with editing. Original sentence: After years of working her way through school, Geeta finally graduated with high honors! Revised sentence: After years of working her way through school, Geeta finally graduated with high honors.

Common uses of periods in abbreviations

Mr.	i.e.	a.m. (or AM)
Ms.	e.g.	p.m. (or PM)
Dr.	etc.

Common omission of periods in abbreviations

NO PERIOD IN US POSTAL SERVICE ABBREVIATIONS FOR STATES

NO PERIOD IN ABBREVIATIONS FOR ORGANIZATION NAMES

NATO	UNESCO	UCLA	BS	BC
IRS	AFL-CIO	NIH	PhD	AD
USA	NAACP	SEC	RN	BCE

NO PERIOD IN ABBREVIATIONS OF ACADEMIC DEGREES

PhD

NO PERIOD IN ABBREVIATIONS FOR ERAS

BCE

NO DOUBLE PERIODS

If a sentence ends with a period marking an abbreviation, do not add a second period.

Example sentence with editing. Original sentence: The train was scheduled for 8:00 a.m.. Revised sentence: The train was scheduled for 8:00 a.m.

NOTE:Check the style of the discipline in which you are writing for the preferred use of periods with abbreviations.

Exercise: Other punctuation marks