• Use periods at the end of abbreviated titles such as Mr., Ms., Dr., Ph.D., M.D., Sr., Jr.  (Note: Miss is not an abbreviation and therefore does not require a period at the end.)
• Use periods in abbreviations of Latin words or phrases: i.e., e.g., et al., etc.
• Use periods for time designations: a.m. and p.m.  (Note: AM and PM are also acceptable; whichever you choose, please be consistent throughout the entire document.)
• Do NOT use periods when abbreviating states: NY, NJ, MD, CA.
• Do NOT use periods in acronyms: SCUBA, NATO, NAACP, IRS.
• Do NOT add a second period if the sentence ends with a period marking an abbreviation:
  • Second base was manned by Jerry Hairston, Jr..
  • Second base was manned by Jerry Hairston, Jr.

Tags: abbreviations, grammar, punctuation

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