DISK:
M (Mint) - Record never played.
NM (Near Mint) - Disc maybe only open or listened to 1/2 times
EX (Excellent) - Disc listened to a few times.
VG (Very good) - Disc listened to several times, good sound quality
G (Good) - Highly listened to disc, decent sound quality
F (Fair) - A very popular album
P (Poor) - Disc treated without care. Insufficient sound quality, "jumps" in listening.
COVER:
M (Mint) - Cover never opened, boxed
NM (Near Mint) Cover as new but not cellophane
EX (Excellent) - Almost new cover
VG (Very good) - Cover and any good inserts.
G (Good) - Cover and any inserts not perfect.
F (Fair) - Cover and any inserts with significant signs of wear, such as folds and tears.