The 10 point Grading Scale:

Poor (P) or Fair (F) 1: A card that has seen serious abuse or has a hole in it.

Good (G) 2: This grade is usually the result of heavy corner rounding, surface wear or creases. Any card with writing on it falls in this category. (Writing other than an autograph of course).

Very Good (VG) 3: A card that looks good from a distance, but on closer inspection several defects can be seen without magnification. This is the highest rating possible on a creased card.

Very Good / Excellent (VGEX) 4: This is the highest grade that a card can have with a small wrinkle. A wrinkle is a crease that can be seen on only one side of the card.

Excellent (EX) 5: This grade is for cards that look really good, but show some wear.

Excellent / Mint (EXMT) 6: A card that looks mint, but upon close examination defects can be seen without magnification.

Near Mint (NM) 7: A card that looks mint, but upon examination with magnification, defects can be seen usually on edges and corners. This grade is often given to cards that are new right out of the packages. This is the best grade I would assume any "raw" card is in unless it has been professionally graded higher. Many sellers will tell you the card they are selling is a higher grade, but unless the card is professionally graded higher, that is just so much seller verbiage. I would always assume any new card right out of the package is Near Mint when making a buying decision. The best dealers describe new raw cards as Near Mint.

Near Mint / Mint (NMMT) 8: A card that looks mint, but upon examination with strong magnification and bright light, very small defects can be detected usually on edges and corners. This is another grade common to new cards right out of the package and professionally graded. Grades higher than Near Mint / Mint are rare. The main reason a new card is not mint is that the cutting blades leave marks on the edges and corners. To consistently get mint cards the blades would have to be sharpened often and the surface of the blades polished to avoid any blade marks.

Mint (MT) 9: Mint basically means very nearly prefect in every regard.

Gem Mint or Perfect (GEM) 10: A mint card with extra appeal. This usually means a brighter than usual surface.

Some graders give in between grades like NM+ to indicate these are cards at the higher end of the grade.