1.a natural object that covers or envelops;
under a covering of dust
2.an artifact that covers something else (usually to protect or shelter or conceal it)
3.the act of concealing the existence of something by obstructing the view of it;
the cover concealed their guns from enemy aircraft
4.the act of protecting something by covering it
5.the work of applying something;
the doctor prescribed a topical application of iodine