A wave function is a mathematical description used in quantum mechanics to represent the quantum state of a particle or system. It contains all the information about the system, including its position, momentum, and energy. The wave function is typically denoted by the Greek letter Ψ (psi) and is a complex-valued function, meaning it has both real and imaginary parts. When the wave function is squared, it gives the probability density of finding a particle in a particular location. This means that the wave function helps predict where a particle, like an electron, is likely to be found when measured. The concept is fundamental to understanding phenomena in quantum physics, such as the behavior of atoms and molecules.