Emdash

An em dash is a punctuation mark that appears as a long horizontal line (—). It is called an em dash because its width traditionally equals the width of an uppercase M in the font, a unit from typesetting known as an em.

In English typography, the em dash is used to create a strong interruption or abrupt change in thought. It can substitute for parentheses, commas, or colons, and it is also used to indicate an abrupt break in dialogue. Some style guides discourage excessive use of em dashes, recommending more conventional punctuation for clarity.

Spacing around the em dash varies by locale. American typography usually presents the dash without spaces on either side; certain British or European styles prefer spaces around the dash.

Encoding and input: the em dash is U+2014 in Unicode, and in HTML it is represented by the entity —. Common keyboard methods include Windows Alt+0151 for an em dash and Alt+0150 for an en dash; on macOS, the em dash is typically produced with Shift+Option+-.

Variants exist for special typographic purposes. The two-em dash (U+2E3A) and the three-em dash (U+2E3B) are historical or specialized marks and are rarely used in modern ordinary text.

See also dash, hyphen, en dash.