From Greek monokhromos, of one color : mono-, mono- + khroma. In Chinese porcelain referring to porcelain decorated with one single uniform colored glaze. Examples of monochromes are:
Monochrome blue porcelain glazes are of several different types depending on how the glaze is made and applied. In principle there are three methods for both coloring agent and glaze - dipping, brushing and (dry and wet) blowing.
These three are possible to confuse but in my view Mazarine blue is the specific clear and bright blue that is produced by painting on the cobalt blue with a brush, before adding the clear porcelain glaze. If so, this Mazarine blue is quite unusual and I have never seen this color on anything except the outside of Kangxi bowls of good quality. Often combined with famille verte enamels.
On larger objects powder blue seems to have been preferred while on other round objects, dipping seems to have been preferred.
As I see it, it is possible that claire de lune and other blue monochromes was invented as a way of putting to use unfired porcelain with underglaze blue decoration, that broke during production. Porcelain glaze is in part made of porcelain paste and it would be a simple matter to add any unfired paste objects - with cobalt decoration and all, to a vat of glaze mixture. If we don't think they used spoiled unfired porcelain like this, we need to believe they throw those away and then used exactly the same ingredients from another stock. I personally find that uneconomic and whatever the Chinese potters ever were, it was not uneconomical.
Beside this there occurs a different type of monochrome blue glaze that might be better off in a section of their own due to their different chemistry, called phosphatic glazes. They are enamels that are mixed with phosphate to make them melt at a lower temperature, and is typically used on pottery rather than porcelain. Thinking of it like this it is in my mind not sure if these phosphatic glazes maybe was added in a second firing and thus maybe should be called enamel rather than glaze- Since this is not easy to tell and does not matter much, it might suffice until further to tell that they differ from normal porcelain glaze by being slightly matte in their surface and does not crackle as a true low temperature lead based glaze would.
If I have very little to do some day I will continue to sort this out. Until further I recommend a close study of Chinese Ceramics by Wang Qingzheng and Chinese Glazes, by Nigel Wood.