The
colon ( : ) is a
punctuation mark consisting of two equally sized dots centered on the same vertical line. A colon precedes an explanation, or an enumeration or list. A colon is also used with
ratios, titles and
subtitles of books, city and publisher in
bibliographies, Biblical citations between chapter and verse, and—in
American English—to separate hours and minutes, for business letter salutations and in
formal letter writing.