| Noun | 1. | upside - the highest or uppermost side of anything; "put your books on top of the desk"; "only the top side of the box was painted"poll - the part of the head between the ears side, face - a surface forming part of the outside of an object; "he examined all sides of the crystal"; "dew dripped from the face of the leaf" rooftop - the top of a (usually flat) roof | |