Aren is one of the base metals from the alloy alignment system based on silver. It represents a gender that is, to some degree, feminine in nature. How one expresses expresses or experiences femininity is defined by them. An aren person can have any alignment or presentation.
History
Aur was originally coin on December 1, 2018 by Hail, the original owner of the Tumblr blog lgbt-alchemy[1]. The plural form was argen. On December 19, 2019 the alloy alignment system was reworked Tired, the new owner of the blog[2]. The name and definition of aren stayed the same during the rework. The plural form of the term is also presumably the same.
The flag is based on the color of silver, and the symbol used is the alchemical symbol for the moon, which is associated with silver.
The name comes from the chemical abbreviation for silver (Ag), though the G is only present in the plural form of the word.