The term was created because most other ways to say that one is attracted to women involve the assumption of one's gender. For example, a straight person attracted to women is typically a man. A gay or lesbian person attracted to women is typically a woman. Although some non-binary people have also adopted this framing of their orientation, some non-binary people are uncomfortable with this, and found the term feminamoric useful for specifying a non-binary person attracted to women.
The masculine counterpart to feminamoric is viramoric. The non-binary counterpart is ceteramoric. A similar term is gynosexual, though some people are uncomfortable identifying with this term as it can have transphobic implications.
The first usage of the term, alongside feminamoric, was in an anonymous tumblr ask to Tumblr user Marlowelune in May 12, 2017. A follow up definition also sent anonymously was posted on the same day.
The term is styled after diamoric and comes from the Latin words femina, meaning "woman", and amor, meaning "love".
In the original flag, there were 5 stripes: maroon, white, pink, white, olive green. Some colors were borrowed from the genderqueer and diamoric flag. The creator and history of the original flag is unknown.
In several proposed new feminamoric flag shades of blue are used to represent non-binary or genderqueer people's attraction to women, for numerous reasons (the Venus symbol is used to symbolize women, the clouds covering the planet Venus' surface are blue, and the mythological roman goddess Venus emerged from the sea when she was born).
In the "yellow banner" non-binary version of the flag by demisexual-yuri, feuillyadeux, bizexuals, and justfolieadoit, the non-binary colors dominate the flag to show that the individual's non-binary-ness is central to the attraction and is what makes the attraction inherently non-straight. The yellow stripes at the side represent women, as Venus is seen as the "female" planet, and is yellow.