sibling

This term serves as a gender-neutral alternative to brother or sister, making it ideal for clinical, legal, or academic contexts where the specific sex of the relative is unknown or irrelevant. It shifts the focus from individual identity to the shared biological or legal kinship.

In a linguistic sense, the word is used to describe a relationship of equality and shared origin. While it primarily refers to human family members, it is frequently employed in technical fields like linguistics or computer science to describe elements that share the same parent node or root.