M (Mint condition) = Absolutely perfect, never played, possibly still sealed.

NM (Near Mint) = Nearly perfect, no obvious signs of wear.  Sleeves or jackets and all inserts will have very minor defects. 

VG+ (Very Good Plus or Excellent) = Shows some signs of play wear, including slight scuffs or very light scratches that don't affect the sound.  Labels, sleeves, and covers may also show slight wear, but in general the record and its sleeve and cover were taken good care of.  

VG (Very Good) = Slightly more pronounced wear, such as surface noise.  Labels, covers, and sleeves may have tape or writing on them.  

G (Good) =  Significant surface noice and scratches, but the record will play without skipping.  Jacket and sleeve will be worn and may have a split seam, tape, lots of writing, or other defects.

F (Fair) = The record may be cracked or badly warped, and it won't play without skipping or repeating.  The label may be very worn, and the sleeve or cover may have water damage, be split on all the seams, or falling apart.  

Records on this website will be graded with the above codes after they are played.  Records that have not yet been played will be sight graded (SG) and will have the "SG" code next to the grade to indicate that the record has not been played.