∅ empty set
∅
U+2205
Copy as
| Character | ∅ | |
|---|---|---|
| Unicode | U+2205 | |
| HTML decimal | ∅ | |
| HTML hexadecimal | ∅ | |
| HTML named entity | ∅ | |
| CSS content | \2205 | |
| JavaScript / UTF-16 | \u2205 | |
| UTF-8 bytes | E2 88 85 |
Meaning & usage
Empty set (∅) belongs to mathematical notation rather than ordinary punctuation.
Use it in formulas, comparisons or technical explanations, and define its role when the context is ambiguous.
U+2205 identifies this exact empty set form; copying the character preserves its Unicode identity, while its appearance depends on the font or emoji renderer.
empty set occupies one Unicode code point. A similar-looking letter, punctuation mark or emoji is not necessarily interchangeable with ∅ in search, filenames or text processing.
How to type empty set
- Windows
- Use Win + . for the emoji and symbol panel, or Character Map for supported fonts. In Microsoft Word, enter each hexadecimal code (2205) and press Alt + X. There is no universal decimal Alt code for this character; legacy Alt codes depend on the code page.
- Mac
- Open Character Viewer with Control + Command + Space and search for empty set. With the Unicode Hex Input keyboard enabled, hold Option and enter the UTF-16 units shown above. Standard Option shortcuts do not cover every Unicode symbol.
- Linux
- In compatible GTK applications, press Ctrl + Shift + U, enter 2205, then Enter. Enter each code point separately for sequences. Other desktops or apps may require their character picker.
- iPhone & Android
- Look for empty set in your emoji keyboard if available, or copy it here and paste. Save frequently used symbols as a text replacement or keyboard shortcut; availability varies by keyboard.