Sorry, Luminosity and luminance

​Hi All,
Our contrast compares relative brightness. Now here is the trick part
luminosity is the measure of the total light energy (brightness) emitted
form a source.​ Luminance is the measure light emitted per unit (of
choice).  If our unit of measure is the pixel (which I think it is) then
then these terms are the same because the energy emitted per pixel in a
color region (luminance) is the same as the energy emitted (luminosity) by
any pixel.

The problem is we use these terms interchangeably in our documents and that
is true for our usage, but it is confusing. We use luminosity but the
formula uses luminance.  How do we make this clear.

Wayne