Single Period When a Sentence Ends with an Abbreviation
The Period
Rulebase Summary
When a sentence ends with an abbreviation that already includes a period, do not add a second period. The abbreviation's period does double duty, also serving as the sentence-ending period. However, other punctuation marks (question marks, exclamation points) are still added after the abbreviation's period when needed.
Morson's Rule 6 · p.4–5 BGGP Abbreviation.15 · p.243
Examples
✗
A. The meeting was scheduled for 10 a.m..
✓
A. The meeting was scheduled for 10 a.m.
One period serves as both abbreviation and sentence end.
✗
A. I spoke with Thomas Hargrove, Jr..
✓
A. I spoke with Thomas Hargrove, Jr.
Never double a period at end of sentence.
Style Guide References (2)
Morson's
Rule 6
Page 4–5
BGGP
Abbreviation.15
Page 243
See also (8)
Same topic Question Mark After a Sentence Ending with an Abbreviation Related Commas with Titles, Degrees, and Designations After Names See Commas Around 'Etc.' in a Series Related Apostrophe for Omission and Contractions Related Apostrophe With Plural of Numbers and Capitalized Abbreviations Related Periods and Lowercase for i.e. and e.g. Related Abbreviating and Capitalizing Titles with Names Related Abbreviating Geographic Words in Proper Names (Saint, Mount, Port, Point, Fort)