sibling
n. countablen. a brother or a sister. You use this word when you want to talk about the other children in your family without saying if they are male or female.
n. a person's brother or sister, regardless of gender. Often used in formal, legal, or sociological contexts to refer to individuals sharing one or both parents.
I have three siblings: two brothers and one sister.
The study examined how sibling rivalry can affect a child's social development during their school years.
While some siblings maintain a close bond throughout adulthood, others may drift apart as their professional lives and personal interests diverge.
First use appears c. 1903, a modern revival of Old English sibling (“relative, a relation, kinsman”), equivalent to sib + -ling. Compare Middle English siblynges pl, sib, sibbe (“relative; kinsman”), German Sippe. The term apparently meant merely kin or relative until the 20th century when it was applied in a way that aided the study of genetics, which led to its specialized use. For example, the OED has a citation in 1902 in which sibling must be defined for those who do not know the intended meaning.
Commonly used in the plural to refer to a group of brothers and sisters.