Delta Equal To Symbol
≜ (delta equal to) is a symbol meaning “is defined as,” commonly used in mathematical and technical writing.
U+225C
The symbol ≜ is read as “is defined as” or “equals by definition.” You’ll often see it when a quantity, function, or rule is introduced. It’s useful when you want to define something without implying that it was previously equal in a worked calculation.
Delta Equal To Symbol Meaning
≜ (Unicode name: DELTA EQUAL TO, U+225C) is a mathematical relation symbol typically read as “is defined as” or “equals by definition.” Unlike a standard equals sign, it emphasizes that the right-hand side establishes the definition of the left-hand side. This is common when specifying new variables, naming functions, or stating identities used later in proofs or derivations. Because it signals definition rather than evaluation, ≜ helps keep mathematical writing precise and easier to follow for readers, especially in textbooks, papers, and technical documentation.
Common uses
- •Defining a variable: writing “x ≜ …” when introducing a new term
- •Stating a function rule: “f(x) ≜ …” to define how the function behaves
- •Naming abbreviations in formulas: “D ≜ …” for a derived expression used later
- •Providing definitions in proofs and derivations without implying prior equality
- •Documenting technical notation in research notes and specifications
Examples
≜ Delta Equal To (≜) Symbol
- ≜Let f(x) ≜ x^2 + 1.
- ≜Define θ ≜ arctan(y/x).
- ≜Set g(t) ≜ e^t − 1 for all real t.
- ≜Let A ≜ {1, 2, 3} be the sample set.
- ≜We use Δ ≜ b^2 − 4ac in the quadratic formula.
Variations
Ready to copy
Technical codes
| Unicode | U+225C | |
| HTML Entity | ≜ | |
| HTML Code | ≜ | |
| CSS | \225C |
FAQ
What does ≜ mean in math?
≜ is read as “is defined as” or “equals by definition,” meaning the expression on the right defines the left side.
Is ≜ the same as the equals sign = ?
No. = typically states equality as an outcome, while ≜ emphasizes that the left-hand side is being defined by the right-hand side.
How do I type ≜ on a keyboard?
You can copy it directly from this page, or use its Unicode codepoint U+225C in systems that support Unicode input.
What are the Unicode/HTML/CSS/JS representations for ≜?
Unicode codepoint: U+225C. HTML entity: ≜. CSS escape: \\225C. JavaScript escape: \\u{225C}.