Punctuation with Abbreviations
When an abbreviation ending in a period is followed by a punctuation mark like a comma, colon, semicolon, or dash, use both the period and the punctuation mark. Don’t omit the period that belongs to the abbreviation.
- It was 11 p.m., and we still hadn’t found our hotel.
- All kinds of animals—dogs, cats, hamsters, etc.—live in this shelter.
- We are open 9 a.m.–6 p.m. on weekdays.
- Lulu loves working at Nusquam Inc.: she gets to play board games for a living.
- The bus leaves at 2 p.m.; the flight, at 4 a.m.
- Is it 2 a.m.?
- It’s 3 a.m.!
- Dash et al.’s findings have far-reaching implications.
- Fish, birds, mammals, etc. . . . are sentient beings that want to live in peace and safety.
This rule applies to commas, dashes, colons, semicolons, question marks, exclamation points, and any other punctuation mark, except a period.
Period after an abbreviation
After an abbreviation ending in a period, don’t add another period to end the sentence. Use just one period, not two.
- It’s 11 p.m.
- Use this app to order bells, whistles, etc.
- Poco still works at Nusquam Inc.
- This paper was published in 1976 by Dash et al.
A single period suffices to mark both the end of the abbreviation and the end of the sentence.
Question mark and exclamation point after an abbreviation
When an abbreviation ending in a period appears at the end of a question or an exclamation, use a question mark or exclamation point as usual after the period. Don’t omit the period.
- Can we meet at 2 p.m.?
- Does Anita still work at Nusquam Inc.?
- Have you reviewed the paper by Dash et al.?
- Wake up. It’s 6 a.m.!
Abbreviation in parentheses or brackets
If an abbreviation ending in a period appears within parentheses (or brackets) after which a sentence ends, use another period after the closing parenthesis to end the sentence.
- This course teaches you how to bake basic breads (white, brown, green, etc.).
- Please call me in the evening (any time after 6 p.m.).
- Poco still works at the same company (Nusquam Inc.).
- Humans spend most of their lives inside their own minds (thinking, dreaming, remembering, planning, despairing, etc.).
However, if the entire sentence is enclosed within parentheses (i.e., the sentence ends within parentheses), use just one period, not two.
- Today we discuss the autonomy of the child. (After all, children are human too.)
- Let’s meet in the evening. (I leave work at 5 p.m.)
- Humans spend most of their lives inside their own minds. (They engage in various mental activities like thinking, remembering, planning, etc.)
Ellipsis after an abbreviation
If an abbreviation ending in a period is followed by an ellipsis, don’t omit the period for the abbreviation. Use the ellipsis as usual after the period.
- Original: Also consider health expenses. Cats, dogs, etc. can have special dietary needs or chronic health conditions and require routine medical checkups, which are often covered by insurance.
Shortened: Also consider health expenses. Cats, dogs, etc. . . . require routine medical checkups, which are often covered by insurance. - Original: Dash et al. published a paper in 1976 in which they investigated how mental states form part of the human circadian rhythm.
Shortened: Dash et al. . . . investigated how mental states form part of the human circadian rhythm.