The term graded applies to a sports card that has been examined by an expert (almost always for a fee) and whose physical condition has been assigned a numerical value. The criteria for grading varies from company to company, but usually include subgrades for the condition of a card's surface, edges, corners and centering, all of which are factors in the overall value.
Grading scales and descriptions also vary, though a card in perfect condition is usually referred to as gem mint or pristine. The term mint is used for a card judged to have only one or two very minor imperfections. Cards certified at these highest conditions are highly valued by collectors and often sell for many times their book values.
Graded cards are sealed in tamper-proof holders to assure they stay in their certified states.