nuanco

The best etymology in the chapter. French nue is a cloud, from Latin nubes, and Esperanto's own word for cloud, nubo at 828, is the same root sitting a few hundred ranks below. To nuer was to shade a colour the way cloud shades a sky, and a nuance was the result. So the word you reach for when an argument turns subtle is, underneath, a weather word. Once you have seen nubo inside nuanco you will not unsee it.

Two senses, and the colour one came first. A nuanco is a shade of a koloro, the difference between two greens that are both green. From there it moved to meaning: the gap between two words that mean almost the same thing, which is what makes translation hard and dictionaries long. Esperanto takes both, and the verb nuanci means to shade something, to qualify a statement so it stops being a blunt instrument.

Distinguish it from a plain difference. A diferenco at 1,059 can be enormous; a nuanco is small by definition, which is why nuanca diferenco is not the tautology it looks like but a way of saying the difference is real and fine. The person who can distingi nuances in a language is past the stage of translating and into the stage of writing.