U+225D "≝" Equal to by Definition Unicode Character

U+225D "≝" Equal to by Definition is a mathematical symbol used to denote that two expressions are identical by definition, often indicating that one side is explicitly defined as equal to the other, rather than being derived or proven. It is commonly employed in formal logic, mathematics, and scientific notation to establish a foundational equivalence in definitions. This symbol combines a standard equals sign with the word "def" written above it, visually reinforcing its role in stipulative definitions.