Example: 1a

Use a period to end most abbreviations.

Abbreviation:

Dr. (Doctor)

Dr. Edward Jenner developed the vaccine for smallpox.

Mr. and Mrs. C. J. Bello have invited us to a dinner party.

Explanation:

Example: 2a

Use a period after initials in a name.

Initials

Stephen’s uncle’s name is J.Q.Adams.

R.L. Stevenson is my favorite author.

Explanation:

Example: 3a

Use periods after the abbreviations for months, a.m., and p.m.

Abbreviation:

Halloween day is on Oct. 31st of this year.

My alarm clock must be broken because it went off at 4 a.m.

Explanation: