HTML Entity for Combining Double Overline (̿)

Beginner
⏱️ 5 min read
📚 Updated: Jun 2026
🎯 1 Code Example
Unicode U+033F
HTML entity for Combining Double Overline (U+033F) tutorial illustration

What You'll Learn

How to display the Combining Double Overline (̿) in HTML and CSS. This character is U+033F (COMBINING DOUBLE OVERLINE) in the Combining Diacritical Marks block (U+0300–U+036F). It appears as a double horizontal line above the preceding base character—for example x̿ for x̿ in math or linguistics notation.

There is no named HTML entity for U+033F. Use ̿, ̿, or \033F in CSS content. Place the entity immediately after the base letter or symbol with no space. Single combining overline is U+0305; standalone overline is U+203E (‾).

⚡ Quick Reference — Double Overline

Unicode U+033F

Combining Diacritical Marks (U+0300–U+036F)

Hex Code ̿

Hexadecimal reference

HTML Code ̿

Decimal reference

Named Entity —

None (use numeric refs)

Reference Table
Name           Value
────────────   ──────────
Unicode        U+033F
Hex code       ̿
HTML code      ̿
Named entity   —
CSS code       \033F
Related        U+0305 = Combining overline; U+203E = Overline character
1

Complete HTML Example

This example shows U+033F using hexadecimal and decimal references, a variable with the double overline above, plus a CSS content escape. There is no named HTML entity:

html
<!DOCTYPE html>
<html>
<head>
 <style>
  #point:after{
   content: "\033F";
  }
 </style>
</head>
<body>
<p>Double Overline using Hexadecimal: &#x033F;</p>
<p>Double Overline using HTML Code: &#831;</p>
<p id="point">Double Overline using CSS Entity: </p>
</body>
</html>
Try it Yourself

🌐 Browser Support

U+033F is supported in modern browsers when placed after a base character and rendered with a font that supports Combining Diacritical Marks:

Chrome 1+
Firefox 1+
Safari 1+
Edge 12+
Opera 4+
Android 4.4+
iOS Safari 1+

👀 Live Preview

See the double overline above a base character (math or linguistic font recommended):

With base character x̿   n̿
Markup pattern x&#x033F;
Standalone mark ̿
Related marks U+033F double overline   U+0305 combining overline   U+203E overline ‾
Monospace refs &#x033F; &#831; \033F

🧠 How It Works

1

Hexadecimal Code

&#x033F; references code point U+033F using hex digits 033F. Place it immediately after the base character (e.g. x&#x033F;).

HTML markup
2

Decimal HTML Code

&#831; uses the decimal Unicode value 831 for the same combining double overline.

HTML markup
3

CSS Entity

\033F is used in CSS stylesheets, particularly in the content property of pseudo-elements like ::before and ::after.

CSS stylesheet
=

Double overline above base character

Place U+033F right after the base character: x̿. Single combining overline is U+0305; standalone overline is U+203E.

✅

Use Cases

The Combining Double Overline (̿) commonly appears in:

📐 Mathematics

Mean (average), complement, or other quantities denoted with a double bar above a variable (e.g. x̿).

🔤 Linguistics

Phonetic or phonological notation where a double overline above a symbol indicates a specific feature.

🎓 Education

Online math or linguistics content that displays symbols with a double overline for correct notation.

📄 Technical docs

Formulas, specifications, or academic papers that use double-overline notation in HTML.

📖 Unicode documentation

Reference pages for Combining Diacritical Marks (U+0300–U+036F).

♿ Accessibility

Use fonts that support combining marks so base + U+033F renders correctly (e.g. x̿) for all users.

💡 Best Practices

Do

  • Place &#x033F; immediately after the base character (e.g. x&#x033F;)
  • Use <meta charset="utf-8"> on pages with combining marks
  • Choose fonts that support Combining Diacritical Marks (Times, Cambria Math, Noto)
  • Use hex or decimal consistently within one document
  • Prefer MathML for complex formulas when layout matters

Don’t

  • Confuse U+033F (double overline) with U+0305 (single combining overline) or U+203E (standalone)
  • Put a space between the base character and the combining entity
  • Expect a named HTML entity—use numeric references only
  • Put CSS escape \033F inside HTML text nodes
  • Assume every font aligns combining double overlines correctly

Key Takeaways

1

Two HTML references for the combining mark

&#x033F; &#831;
2

For CSS stylesheets, use the escape in the content property

\033F
3

U+033F combining double overline—place after base character

4

Example: x̿ with x&#x033F;

5

No named entity for U+033F — use numeric references

❓ Frequently Asked Questions

Use &#x033F; (hex), &#831; (decimal), or \033F in CSS content. Place the entity immediately after the base character (e.g. x&#x033F; for x̿). There is no named HTML entity for U+033F.
U+033F (COMBINING DOUBLE OVERLINE). Combining Diacritical Marks block (U+0300–U+036F). Hex 033F, decimal 831. Double horizontal line above the preceding base character.
When you need a double overline above a base character for math notation (mean, complement), linguistics, or technical documentation. Place the entity right after the base character with no space.
HTML numeric references (&#831; or &#x033F;) go in markup after a base character. The CSS escape \033F is used in stylesheets, typically in the content property of pseudo-elements.
U+033F is a combining nonspacing mark. It attaches above the preceding base character (e.g. x + ̿ = x̿). Use x&#x033F; or x&#831; in HTML with no space between the character and the entity.

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About the author

Mari Selvan M P
Mari Selvan M P 🔗

Developer, cloud engineer, and technical writer

  • Experience 12 years building web and cloud systems
  • Focus Full Stack Development, AWS, and Developer Education

I write practical tutorials so students and working developers can learn by doing—from databases and APIs to deployment on AWS.

AWS Certified Developer – Associate (Credly)

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