The binary genders are the two genders used in the western gender binary system: women and men. The opposite of binary is nonbinary, which includes any genders that are not completely and solely male or completely and solely female. Binary people can be cisgender or transgender. It is also a gender arity.
The gender binary is used to describe the misconception that man and woman are the only two possible genders and they can be assigned on the based on genitalia. This system often also typically enforces a masculine gender expression/presentation for men and feminine gender expression/presentation for women.