In 2014, Tumblr user drkiriko/publicmiddleschool created and defined the terms monagender, monegender, and selenogender as: "A gender experience of fluidity in which your perception of your gender, or even the foundation of your gender itself, shifts in a consistent way in many ways over a period of days, weeks, months, or even years, especially with long or short periods of various xenogender based feelings and perceptions. like the phases of the moon, your gender experiences similarly phases over time, in a same or similar order, consistently. i suppose this would be a subset of genderfluidness with a focus on order & xenogender feelings or feelings of gender that cannot be contained in a human understanding, but not always."