Polyandry is a relationship in which a woman has a relationship or marriage with multiple/many men. This could be due to religious beliefs or cultural acts, but it is not required.
Flag
The polyandry flag was coined by Deviantart user NonMonoPrideFlags on December 3rd, 2015.
Resources
https://www.deviantart.com/nonmonoprideflags/art/Polyandry-Pride-Flag-576035693