comma
The mark that separates parts of a sentence to show its structure.
A comma separates parts of a sentence to show its structure. It divides items in a series, marks the boundary after an introductory element or between clauses joined by a conjunction, and sets off words that interrupt or add to the main sentence. Grammar and meaning decide where a comma goes, not the pauses of speech: a natural pause does not by itself call for a comma, and some commas fall where no speaker would pause. Each use of the comma has its own entry, listed under Comma.
Examples
UseWe packed tents, stoves, and lanterns. (The commas divide the items in the series.)
UseOn Monday, the office reopened. (The comma marks where the introductory phrase ends and the main clause begins.)
UseThe rain stopped, and the game resumed. (The comma comes before the conjunction that joins the two clauses.)
UseOur manager, Dana Ruiz, approved the plan. (The pair of commas sets off the name, which adds to the main sentence.)
AvoidThe students in the back row, asked questions. (The speaker might pause after the long subject, but a comma never separates a subject from its verb.)
AvoidThe office reopened, the staff returned. (A comma alone cannot join two complete sentences.)