[Luna Azul]

"Forro" is actually a very useful word. We use it when we don't know the real name of something that's covering something else.

It can be said instead of: cubierta, funda, revestimiento, sobrecubierta, recubrimiento, envoltura, piel, etc.

It's also a conjugation of the verb "forrar" (to line, to cover) in the first person singular: "yo forro"