Wave vector is a term commonly used in physics to describe the direction and magnitude of a wave's propagation. However, there are several synonyms that can be used to describe this concept. One common synonym is the term wave number, which represents the number of waves per unit distance. Another synonym is the phase vector, which describes the phase of the wave. Additionally, the term propagation vector is often used to describe wave vector in electromagnetic wave theory. Other synonyms include wavenumber vector, phase velocity vector, and group velocity vector. These synonyms can be used interchangeably to describe the behavior and properties of waves in a variety of contexts.