brother-sister
UK[ˈbrʌðə ˈsɪstə]US[ˈbrʌðər ˈsɪstər]
adj
Relating to or involving a brother and a sister.
adj
Denoting a relationship or interaction between a male and a female sibling.
Etymology
The term 'brother-sister' is a modern English compound that directly juxtaposes two of the most fundamental kinship terms. Each component has a distinct, ancient lineage: 'brother' descends from a PIE root meaning 'male member of the family/clan,' while 'sister' derives from a PIE root meaning 'female member of the family/clan.' Their combination into a hyphenated adjective is a logical and transparent grammatical construction in English, used to specify a dyadic relationship that is exclusively fraternal and sororal. This compound efficiently encapsulates the specific dynamic of a cross-gender sibling bond, a concept universally recognized but here lexically formalized in modern usage.
Analysis
This is a hyphenated compound adjective formed from two simplex nouns, 'brother' and 'sister'. 'Brother' originates from Old English 'brōþor', from Proto-Germanic 'brōþēr', from Proto-Indo-European 'bʰréh₂tēr'. 'Sister' originates from Old Norse 'systir', replacing the Old English 'sweostor', both from Proto-Germanic 'swestēr', from Proto-Indo-European 'swésōr'.
Examples
They have a very close brother-sister relationship.
The story explores the complex brother-sister dynamic within the royal family.
The foundation is a brother-sister organization, with each branch supporting the other.