nanosteradian

noun1

1. •
   One billionth (10⁻⁹) of a steradian.

   • Its peak intensity in this model of the Sgr B2 cloud is Iₗᵢₙₑ = 0.014 Jy nsr⁻¹, where 1 Jy = 10⁻²⁶ Wm⁻²Hz⁻¹ and nsr stands for one nanosteradian (10⁻⁹ sr). — 2000