A sister is a female sibling, someone who shares at least one parent with you. Sisters can be biological, meaning they are born into the same family, or they can be adopted, meaning they join the family through legal means. Having a sister often means having a built-in friend, someone to share secrets, laughter, and even challenges with. Sisters can play many roles in each other's lives, from confidantes to rivals. They may share interests, like sports or music, and create lasting memories together. The bond between sisters can be strong, providing support and love throughout life's ups and downs.