Standard set of marks used in written and printed texts to clarify meaning and to separate sentences, words, and parts of words. It often marks discourse features such as intonational contours and pauses. It may also convey information about a word (e.g., hyphens in compound words) unrelated to speech patterns. In English, the period (.) marks the end of a sentence or an abbreviation. The comma (,) usually separates clauses, phrases, or items in a series. The colon (:) often introduces an explanation or series of examples. The semicolon (;) usually separates independent clauses. The em-dash () marks an abrupt transition. The exclamation point (!) signals surprise. The question mark (?) signals a question. The apostrophe (') marks the possessive case or the omission of letters. Quotation marks ( ) set off either quoted words or words used with special significance. Interpolations in a sentence are marked by brackets ([ ]) or parentheses ( ).