fraternal
adj.adj. describing the relationship between brothers or people who feel like brothers. It is also used for twins who are not identical because they come from two different eggs.
adj. relating to brothers or a brotherhood; characterised by brotherly affection or shared interests. In a biological context, refers to non-identical twins developed from separate ova.
The two friends shared a strong fraternal bond.
The organisation was founded on fraternal principles to provide support and community for its members.
While identical twins share nearly all their genetic material, fraternal twins are no more genetically similar than any other pair of siblings born at different times.
PIE word *bʰréh₂tēr Borrowed from Middle French fraternel, from Medieval Latin frāternālis (“fraternal”), from Latin frāternus (“of or pertaining to a brother, fraternal”), from frāter (“brother”).
Often used in formal or legal contexts to describe organisations (fraternal orders) or in biology to distinguish twin types.