If this is still about foundation, as in your previous question.

Coverage refers to the opacity of the makeup, or how much it will conceal on the skin.
Sheer is the most transparent and contains the least amount of pigment. It will not hide discolorations on the skin but it can minimise the contrast between the discoloration and the rest of the skin tone. Although pigment technology has evolved dramatically since 2004, the traditional protocol for sheer foundations called for pigment to comprise 8–13% of the finished formula.
Light can cover unevenness and slight blotchiness, but is not opaque enough to cover freckles. It contains 13–18% pigment.
Medium coverage can, when set with a tinted (instead of translucent) powder, cover freckles, discolorations, blotchiness, and red marks left by pimples. It contains 18–23% pigment.
Full coverage is very opaque, and used to cover birthmarks, vitiligo, hyperpigmentation and scars. It is sometimes referred to as “corrective” or “camouflage” make-up. In general it contains up to 35% pigment, though professional brands, designed for use on stage, can contain up to 50% pigment. An example is Colortration.
http://en.wikipedia.org/wiki/Foundation_(cosmetics)#Coverage

--------------------------------------------------
Note added at 40 mins (2014-12-05 18:15:03 GMT)
--------------------------------------------------

The plural of "coverage" is fairly common in this specific context:

Following are the basic types of foundation finishes for different coverages and skin types...
http://www.amakeupdiary.com/foundation-basics/

Everyday Minerals have 4 different coverages to choose between ...
http://www.makeuptalk.com/f/topic/96878-mineral-makeup-diffe...

MAC - Foundation & Concealers: various shade, formulas, and coverages
http://www.specktra.net/t/129969/mac-foundation-concealers-v...