J21

J21 stands for:

Acute bronchiolitis , ICD-10 code for inflammation of the smallest, cartilaginous bronchi
HMSwS Södermanland , destroyer of the Swedish Navy
Johnson body J ₂₁ , the elongated pentagonal rotunda
Journal21 , Swiss online newspaper
S / 2003 J 21 , one of the smaller moons of the planet Jupiter
Soko J-21 Jastreb , a Yugoslav fighter aircraft