Suresure!
ATRIN, or Atrinary In Nature, is a term for individuals whose gender encompasses all types of gender that do not fall into the gender trinary (masc, fem, neutral/nonbinary). Examples of atrinary genders would be aporagender, maverique, or comgender.
The basic component of an atrinary gender is that it does not feel masculine, feminine, neutral, or void of gender in any way, while still having a gendered feeling. It falls outside the nonbinary spectrum in that it goes outside the nonbinary concept (nonbinary = not male/masc or female/fem). Nonbinary gender feelings are called ‘neutral,’ though this isn’t always a suitable description. (Neutral can mean ‘not either masculine or feminine,’ or can mean ‘muted but still present’ or ‘undefined’.) Lack of gender feelings (agender spectrum) also falls under nonbinary.
Atrinary genders are not aligned to male, female, or neutral, and are not absent of gender feeling. Instead they have their own alignment all to themselves, and can be defined in many different ways. I’d say neurogenders and xenogenders fall into this umbrella but I feel that’s up to the person and I might be misunderstanding the concept of those two groups. (At least, I feel neurogenders and xenogenders don’t inherently have a masculine, feminine, neutral or empty gender energy the same way male/female/nonbinary genders do, but CAN have them, depending on the person.)
A good idea of this would be maverique, which is a gender that has no alignment whatsoever, but still has conviction, pride and its own power, a gender that is strong and defies the manner of gender in its traditional concepts. It’s not masculine, or feminine, or neutral, and it’s the opposite of agender entirely. The gender has its own method of expression, which can be of any energy type – orderly, happy, aggressive, high energy, low energy, wild, empowering – you get the idea. (I hope.)
So back on topic, someone who is Atrin experiences all genders that are (or their gender just in general is) outside the atrinary spectrum. How their gender expresses itself is different for each individual and can only be defined by them.