Real Dictionary

etch
If you say that feelings are etched on someone's face, you mean that the person is very strongly affected by them, and you can see this in their appearance.
verb: If a line or pattern is etched into a surface, it is cut into the surface by means of acid or a sharp tool. You can also say that a surface is etched with a line or pattern.

etch in American English
to make (a drawing, design, etc.) on metal, glass, etc. by the action of an acid, esp. by coating the surface with wax and letting acid eat into the lines or areas laid bare with a special needle
to make etchings
intransitive verb: to practice the art of etching
noun: an acid used for etching
transitive verb: to cut, bite, or corrode with an acid or the like; engrave with an acid or the like, as to form a design in furrows that when charged with ink will give an impression on paper

etch in British English
verb: to wear away the surface of (a metal, glass, etc) by chemical action, esp the action of an acid