ダッシュ
文の一部を区切ったり範囲を示したりする句読記号。Unicodeはハイフン（‐）・エンダッシュ（–）・エムダッシュ（—）・図表ダッシュ（‒）などを定義しています。
What is a Dash?
In typography, dash refers to a family of horizontal line characters that perform distinct semantic roles. The word "dash" is often used loosely, but each member of the dash family has a specific purpose: the hyphen joins words, the en dash marks ranges, the em dash marks interruptions or parenthetical asides, and the minus sign is a mathematical operator. Confusing them is one of the most common typographic errors in digital publishing.
The Dash Family
| Character | Unicode | Name | Width | Primary Use |
|---|---|---|---|---|
| - | U+002D | Hyphen-minus | Narrow | Keyboard input, compound words, programming |
| ‐ | U+2010 | Hyphen | Same as - | True hyphen for breaking words |
| ‑ | U+2011 | Non-breaking Hyphen | Same | Hyphen that prevents line breaks |
| – | U+2013 | En Dash | 1 en (~½ em) | Ranges, scores, compound proper nouns |
| — | U+2014 | Em Dash | 1 em | Parenthetical aside, interruption |
| ― | U+2015 | Horizontal Bar | ~1 em | Dialogue attribution (in some typographic traditions) |
| − | U+2212 | Minus Sign | Math-width | Mathematical subtraction |
The Hyphen-Minus Problem
The hyphen-minus (U+002D, the - on your keyboard) is a compromise character that computers inherited from typewriter culture. It serves as hyphen, minus sign, and even dash in informal writing — but typographically it should only be used as a hyphen for word breaks or in code/programming contexts.
Smart text editors and word processors auto-convert -- to an en dash and --- to an em dash. HTML entities provide the correct characters:
– <!-- en dash – -->
— <!-- em dash — -->
− <!-- minus sign − -->
En Dash Usage (–)
The en dash (U+2013) is used for: - Ranges: pages 10–25, the 2020–2024 period, Monday–Friday - Scores: the final score was 3–2 - Compound modifiers with proper nouns: the New York–London flight
Keyboard entry:
- macOS: Option + Hyphen
- Windows: Alt + 0150 (numpad)
- HTML: – or –
Em Dash Usage (—)
The em dash (U+2014) is the most versatile dash, used for: - Parenthetical aside: She finally arrived—three hours late—with no explanation. - Interruption: "I can't believe you would—" she stopped herself. - Emphasis: Only one thing mattered now—survival.
Em dashes may appear with or without spaces depending on house style (American style: no spaces; British style: spaced).
Keyboard entry:
- macOS: Shift + Option + Hyphen
- Windows: Alt + 0151 (numpad)
- HTML: — or —
Quick Facts
| Property | Value |
|---|---|
| Keyboard hyphen-minus | U+002D — the - key |
| En dash | U+2013, width of letter "n", for ranges |
| Em dash | U+2014, width of letter "m", for parentheticals |
| Minus sign | U+2212, mathematical subtraction |
| macOS en dash shortcut | Option + - |
| macOS em dash shortcut | Shift + Option + - |
| HTML en dash entity | – |
| HTML em dash entity | — |
関連用語
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文字が右から左に流れるテキスト方向。アラビア語・ヘブライ語・ターナ文字などで使われ、正しい表示のために双方向アルゴリズムが必要です。
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視覚的な調和のために特定の文字ペア（例：AV・To・LT）間のスペーシングを調整すること。Unicodeの概念ではなくフォント機能ですが、Unicodeテキストのレンダリングに影響します。
フォントによってレンダリングされる文字の視覚的表現。1つの文字が複数のグリフを持つ場合があり（合字・文脈形態）、1つのグリフが複数の文字を表す場合もあります。
小文字の高さの大文字字形。CSS：font-variant: small-caps。Unicodeにはラテン拡張（ᴀ〜ᴢ）に実際のスモールキャップス文字があります。
前進幅がゼロの文字 — レンダリングでは見えませんがテキスト動作に影響します。ZWSP（単語区切り）・ZWJ（結合）・ZWNJ（結合防止）・WJ（改行防止）などがあります。