A horizontal line used to separate clauses within a sentence or to indicate the interruption of a sentence. Not to be confused with hyphens. Hyphens should not be used to separate clauses or interrupt sentences, and em-dashes should not be used to join related words within a clause.

A rare type of dash rarely seen outside of Microsft Word. It is generated by a secret key-combination. In many cases em dashes can be seamlessly connected to make a line (Urban Dictionary is one exception).