1. a punctuation mark (:) used to precede a list of items, a quotation, or an expansion or explanation.
▪ a colon used in various technical and formulaic contexts, for example a statement of proportion between two numbers, or to separate hours from minutes (and minutes from seconds) in a numerical statement of time:"10:1"
Word Originmid 16th century (as a term in rhetoric denoting a section of a complex sentence, or a pause before it): via Latin from Greek kōlon ‘limb, clause’.