Nappe

Nappe is the act of coating food with a sauce. It is also a way to describe the consistency of a sauce.

A good test to check for the correct consistency is to coat the back of a spoon with the sauce, then run your finger over the back of the spoon, forming a line. If the sauce holds its shape and doesn't immediately fill in the line, and isn't too thick as to leave a thick layer of sauce on the spoon, the sauce is the correct consistency.