emdashとは 意味・読み方・使い方

別の表記

• emdash, em-dash, m dash

語源

Named for its width, which is equal to the width of the letter m or M, or approximately twice the width of an en dash.

発音

名詞

em dash (plural em dashes)

1. (typography) The symbol (—) (used to demarcate a parenthetical thought or to indicate a break, or for emphasis); a one-em or long dash.

   Synonyms: em rule, m-rule, mutton dash

   • 2025 December 3, Sam Kriss, “Why Does A.I. Write Like … That?”, in The New York Times Magazine‎, New York, N.Y.: The New York Times Company, →ISSN, →OCLC, archived from the original on 3 December 2025:

     So now, no matter where it’s coming from or why, millions of people recognize the em dash as a sign of zero-effort, low-quality algorithmic slop.

使用する際の注意点

In recent usage, some style guides (especially in the UK and Canada) have proscribed the parenthetical em dash (—), instead mandating the use of a spaced en dash (–),[dead link][dead link] though this is not universally accepted. For example:

The room – dark and depressing – was at the end of the corridor.

Rather than:

The room—dark and depressing—was at the end of the corridor.

These symbols are often identical in appearance and can be used as quotation dashes:

• — (em dash)
• ― (horizontal bar)

関連する語

• en dash
• hyphen
• rule

参照

アナグラム

• Hameds, mashed, shamed

名詞

em-dash (plural em-dashes)

1. Alternative form of em dash.

アナグラム

• Hameds, mashed, shamed