U+2218 "∘" Ring Operator Unicode Character
Unicode Version 17.0
∘
U+2218 "∘" Ring Operator is a mathematical symbol commonly used to represent function composition, meaning that applying the operator to two functions f and g yields a new function that applies g first and then f, denoted as (f ∘ g)(x) = f(g(x)). It also appears in algebra, category theory, and logic to denote binary operations such as the composition of relations or the Hadamard product in matrix algebra. This character is distinct from the degree sign and the superscript lowercase letter o, as it is specifically designed for mathematical notation with consistent spacing and placement.
General Properties
| Code Point | U+2218 |
| Version Added | 1.1 |
| Name | Ring Operator |
| Block | Mathematical Operators |
| General Category | Math Symbol |
| Canonical Combining Class | Not Reordered |
| Bidirectional Class | Other Neutral |
Encodings
| HTML Decimal Encoding | ∘ |
| HTML Hex Encoding | ∘ |
| UTF-8 Encoding | 0xE2 0x88 0x98 |
| UTF-16 Encoding | 0x2218 |
| UTF-32 Encoding | 0x00002218 |
| C/C++/Java Escape | \u2218 |
Unicode Properties
| NFC Quick Check | Yes |
| NFD Quick Check | Yes |
| NFKC Quick Check | Yes |
| NFKD Quick Check | Yes |
| Numeric Type | None |
| Numeric Value | NaN |
| Line Break | Alphabetic |
| Script | Common |
| Script Extensions | Common |
| Indic Syllabic Category | Other |
| Pattern Syntax | Yes |
| Math | Yes |
| Vertical Orientation | Rotated |
| Grapheme Base | Yes |
| Grapheme Cluster Break | Other |
| Word Break | Other |
| Sentence Break | Other |