The Dirac delta function is also known as the unit impulse function, impulse function, delta function, and Dirac function. It is a mathematical object that is used to describe a point or spike in a continuous signal or function. The delta function has a value of zero everywhere except at one particular point, where it goes to infinity, hence the term unit impulse. This function is commonly used in signal processing, quantum mechanics, and other fields of mathematics and physics. The different names for the Dirac delta function are used interchangeably, depending on the context. However, the fundamental concept and properties of this mathematical object remain the same, regardless of the name used to describe it.