J21
J21 stands for:
- Acute bronchiolitis, an inflammation of the smallest bronchi cartilage loose after the ICD -10 code
- HMSwS Södermanland, a destroyer of the Swedish Navy
- S/2003 J 21, one of the smaller moons of Jupiter
- The Johnson - J21 body, the extended Fünfecksrotunde
- Disambiguation
- Abbreviation