If you have someone that you treat as if he were your brother, this is an example of a relationship would be described as fraternal.
- of or characteristic of a brother or brothers; brotherly
- of or like a fraternal order or a fraternity
- designating twins, of either the same or different sexes, developed from separately fertilized ova and thus having hereditary characteristics not necessarily the same
Origin of fraternalMiddle English from Medieval Latin fraternalis from Classical Latin fraternus, brotherly from frater, brother
- a. Of or relating to brothers: a close fraternal tie.b. Showing comradeship; brotherly.
- a. Of or constituting a fraternity: a fraternal association.b. Roman Catholic Church Of or constituting a mendicant order such as the Dominicans or Franciscans.
- Biology Of, relating to, or being a twin developed from two separately fertilized ova; dizygotic.
Origin of fraternalMiddle English from Old French fraternel from Medieval Latin frāternālis from Latin frāternus from frāter brother ; see bhrāter- in Indo-European roots.
(comparative more fraternal, superlative most fraternal)
- Of brothers (fraternal twins).
- Related through a brother (fraternal nephew).
- In need of a brother or sister or friend.
- Like brothers (fraternal cousins).
- Brotherly, befitting or of a brother or brothers.
- Friendly or brotherly (e.g. fraternal relations between socialist parties in different countries).
- Being or of a society of men linked in brotherly union (fraternal society).
- platonic (as fraternal love - brotherly love).
From Middle French fraternel, from Medieval Latin frāternālis (“fraternal”), from Latin frāternus (“of or pertaining to a brother, fraternal”), from frāter (“brother”).