Polygender refers to an individual that identifies as being one or more gender. The individual might identify with multiple genders and express these genders as a mix or identify as different genders at different times.
Polygender individuals identify as being non-binary or multi-gender. In cases where an individual identifies as different genders at different times, this is often referred to as being gender fluid which is to say that gender is not set in stone. It is a model of gender that moves along a spectrum and may not be the same at different points in time.
