Illumination unit and Light unit

Illumination unit noun - A measure of illumination.

Light unit and illumination unit are semantically related. In some cases you can use "Light unit" instead a noun phrase "Illumination unit".

Light unit noun - A measure of the visible electromagnetic radiation.

Illumination unit and light unit are semantically related. Sometimes you can replace phrase "Illumination unit" with "Light unit", this phrases are similar.