The term "wavefunction" is a fundamental concept in quantum mechanics and refers to the mathematical representation of a quantum system. There are several other phrases that can be used as synonyms for wavefunction, including probability amplitude, state vector, and quantum state. These terms all describe the same concept, which is essentially a mathematical description of a system's quantum state that allows us to predict the probability of various outcomes when that system is measured or observed. While each of these phrases may have slightly different connotations or implications, they are generally interchangeable and refer to the same underlying idea.