The Kronecker Delta, also known as the Kronecker symbol or Kronecker function, is a mathematical symbol represented by the uppercase Greek letter delta (Δ) with subscripts. It is often used in mathematics, physics, and engineering to represent a function that equals 1 if the subscripts are equal, and 0 otherwise. The Kronecker Delta has several synonyms such as identity matrix, Dirac function, unit function, indicator function, and discrete delta function. It is also frequently called the Kronecker delta because it was first introduced by German mathematician Leopold Kronecker. These synonyms are used interchangeably and can be used to represent the same function.