Hello no such word is found any where. Hope it has to be intensity. OK?
Intensity is the quantity and not the quality. We say bulb is glowing so dim. That torch gives bright light. Hence dim means less intense and bright means more intense. In case of sound we say, " I can't hear you, please a little bit louder."
So loudness is related to intensity. In case of radiations such as Xray, we mean the intensity as the number of Xray photons crossing unit area in one second normally. The hair density is more for some people. It means in a given area the number of scalps will be more in number and they are closer each other. For some other people the density will be less so they have thin tail of hair. So hair is intense for some and not so intense for some others.