Nonbinary means different things to different people. Some nonbinary people do not identify with any gender at all.
Non-binary is identifying between, beyond or with both gender categories female/male.
The creator of the nonbinary pride flag is Kye Rowan in 2014.
The colors of the flag have different meanings, the yellow stripe represents people whose gender is outside the binary, the white stripe, people with multiple or all genders, purple people with genders considered to be a mix of male and female, and black for people who identify as not having one gender.