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 a real and an imaginary part. 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 of wave functions is fundamental to understanding the behavior of particles at the quantum level, including phenomena like superposition and entanglement.