Equal To By Definition Symbol
≝ denotes that the right-hand side is defined to equal the left-hand side.
U+225D
The symbol “≝” is read as “equal to by definition.” It’s commonly used when something is introduced or specified, rather than merely asserted as an equality. Use it to clarify definitions in math and technical writing.
Equal To By Definition Symbol Meaning
The symbol ≝ (Unicode U+225D) means “equal to by definition.” Unlike a plain equals sign (often interpreted as a general equality), ≝ signals that the expression on the right is being used to define or specify the meaning of the expression on the left. You’ll see it when introducing a term, setting a convention, or formalizing an identifier (for example, defining a function, variable, or operator). In technical documents, it helps readers distinguish between claims that something is equal and statements that something is being defined.
Common uses
- •Defining a function or operation: f(x) ≝ expression
- •Introducing a constant or variable: c ≝ 3.14
- •Stating a notation convention: ||v|| ≝ sqrt(v·v)
- •Specifying rules in logic or formal systems: A ≝ B
- •Clarifying definitions in technical writing and specs
Examples
≝ Equal to by Definition (Definition Equals)
- ≝f(x) ≝ x^2 + 1
- ≝Let g(x) ≝ (x − 1)/(x + 1).
- ≝Distance d(x, y) ≝ sqrt((x − y)^2).
- ≝π ≝ 3.14159 (approximation in this context).
- ≝operator ⊕ ≝ (a, b) ↦ a+b.
Variations
Ready to copy
Technical codes
| Unicode | U+225D | |
| HTML Entity | ≝ | |
| HTML Code | ≝ | |
| CSS | \225D |
FAQ
What does the Equal To By Definition symbol mean?
The symbol ≝ (Unicode U+225D) means “equal to by definition.” Unlike a plain equals sign (often interpreted as a general equality), ≝ signals that the expression on the right is being used to define or specify the meaning of the expression on the left. You’ll see it when introducing a term, setting a convention, or formalizing an identifier (for example, defining a function, variable, or operator). In technical documents, it helps readers distinguish between claims that something is equal and statements that something is being defined.
Is ≝ the same as the equals sign =?
No. “≝” is read as “equal to by definition,” meaning you’re defining something. “=” is typically used for general equality or assertions.
Where can I use ≝?
You can use it in math notes, formulas, logic, and technical specifications when introducing definitions, constants, functions, or notation.
What is the Unicode for ≝?
The symbol ≝ is Unicode U+225D.
How do I type ≝ on the web or in code?
You can copy the character directly, or use HTML entity ≝ and CSS escape \\225D. JavaScript can use \\u{225D}.