The vinyl/record standard that dealers worldwide adhere to:

M Mint Must be in perfect condition with no audible or visible defects whatsoever. The record and cover/sleeve should be exactly as brand new.
 
NM Near Mint Almost mint but has one or two minor visible marks on the cover/sleeve or surface with sound quality remaining almost perfect.

EX Excellent Not perfect. There may be a few very light surface marks on vinyl and some very minor deterioration in sound quality. The cover/sleeve may show very slight wear, nothing serious 

VG Very Good The surface and cover/sleeve shows visible signs of wear due to the fact that it has been played on a regular basis. There will be some audible surface noise but it will not effect the listening experience too much.

G Good The sound quality has deteriorated due to having been played often. The cover/sleeve and surface will show considerable signs of wear and tear with some possible damage.

F Fair Has been neglected, but is still playable. There will be major audible defects such as loud clicks or jumping. The cover/sleeve may be badly damaged.

P Poor Technically playable, but with serious deterioration in condition and sound quality. The cover/sleeve will be badly damaged.

VP Very Poor In terrible condition and absolutely unplayable. Would only be of use as a last resort to complete a collection. 

Courtesy of www.recordcollector.co.uk