Periods

Period Pete

“Stop here? Stop there? Why not stop twice?”

What's the problem?

A period ends a statement (a declarative sentence) or a mild command. It marks a full stop between complete thoughts; a semicolon or an appropriate conjunction can be other valid ways to separate them without changing the facts. A question reported indirectly inside a declarative sentence ("She asked whether the room was free") normally ends with a period; spoken intonation, echo questions and some other contexts can differ. Periods also mark many abbreviations under our house style (a.m., Dr., etc., U.S.); when a sentence ends with one, a single period does both jobs. Some abbreviations, such as PDF and FBI, and acronyms pronounced as words, such as NASA, are written without periods in our house style. Writers sometimes use fragments on purpose; a period after a fragment can be an intentional stylistic choice.

Context: An email reporting separate facts and an indirect question. House style: periods in a.m./p.m.

✗ Period trouble

The workshop starts at 9 a.m.. Bring a laptop the room has outlets. Dana asked whether parking is free?

✓ Clear stop

The workshop starts at 9 a.m. Bring a laptop. The room has outlets. Dana asked whether parking is free.

Why it works

The abbreviation's period also ends the sentence. A period marks where the first complete thought ends ("Bring a laptop"); a semicolon would also work. Dana's question is reported within a statement, so the sentence ends with a period.