When I looked in the dictionary under "sisterhood", it said "the state or relation of being a sister"; it's more than just that. Sisterhood is a feeling beyond words. It's a feeling of warmth and comfort. It means knowing that someone will be there for you under all circumstances, that they accept you for who you are, and that they will support you in everything you do. Despite our outward appearances, personalities, likes and dislikes, and best of all, how we go about handling certain situations, sister stick together through thick and thin. They can be mistaken for a family of girls who love one another in spite of their similarities and differences. .
One thing that all siblings do is love and care for one another. Despite the fact that they don't get along sometimes, or extremely dislike each other's guts, siblings stick together. For example, although I was born into a family of annoying boys, I love my brothers. They get on my last nerve sometimes, but I would do anything for them. And although I am not a truculent person, if someone ever hurt one of my brothers or treated them in a way they didn't want to be treated, I would have a problem with that. In the presence of sisterhood, it's exactly the same. You have to go beyond friendship and care for one another as if they were your true siblings. You have to listen to the each other, give advice, "have each other's backs", and lend a shoulder to cry on. .
In any relationship trust and honesty are the backbones. Whether it's a parent to child relationship, sister-to-sister relationship, or boyfriend to girlfriend relationship, it's important that you can trust and be honest with the other person. You should be able to go to your "sister" with any problems you are having, or if you are seeking advice. You should be able to trust that what you discuss between the other person will be kept confidential (which doesn't give you the right to tell anyone else's business).