What it means
The left side is a new name for the right side. Books also write ≜ or ≔, or put def over an equals sign.
Read aloud in real formulas
f(x) := x² + 1
Aethel says
f of x is defined as x squared plus 1
this defines the function f
Typing it
- LaTeX
- :=, \coloneqq, \triangleq
- Unicode
- U+2254, U+225C
Questions
How do you say := out loud?
It is usually read “is defined as”.
What does := mean in maths?
The left side is a new name for the right side. Books also write ≜ or ≔, or put def over an equals sign.
How do you type :=?
In LaTeX, write :=, \coloneqq, \triangleq. Its Unicode code point is U+2254, U+225C.