WattPerSquareMetreSteradian

`Watt per steradian per square metre` is the SI unit of radiance (W·sr⁻¹·m⁻²), while that of spectral radiance in frequency is the watt per steradian per square metre per hertz (W·sr⁻¹·m⁻²·Hz⁻¹) and that of spectral radiance in wavelength is the watt per steradian per square metre, per metre (W·sr⁻¹·m⁻³), commonly the watt per steradian per square metre per nanometre (W·sr⁻¹·m⁻²·nm⁻¹). It has a dimension of ML⁻⁴T⁻³ where M is mass, L is length, and T is time. This unit is the standard SI unit in this category.

-- QUDT