FRJ
The abbreviation FRJ stands for:
- Federal Republic of Yugoslavia , a former federal state in Southeastern Europe
- Research reactor Jülich 1 (FRJ-1) or research reactor Jülich 2 (FRJ-2), former nuclear reactors at Forschungszentrum Jülich
- Field Robot Junior , a student competition for field robots
FR-J stands for:
- Former ISO-3166-2 code of the French region Île-de-France , replaced by FR-IDF since 2016
