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 fraternalis, from Latin fraternus, from frater, brother; see bhrater- 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”).