NEAR MINT
Unread, or read so carefully you cannot tell. Square, tight, unmarked.The book trade calls this Fine.
EXCELLENT
Read once. One fault at most, and it is named.The trade calls this Near Fine.
VERY GOOD
Shelf wear and handling. Sound, complete, clean inside.
GOOD
Well read. Faults you would notice at arm's length.
FAIR
Tired but complete. Bought to be read, not shelved.
POOR
Broken, marked or missing something. Priced as such.
NEAR MINT
Flat spine, sharp corners, the gloss still on it.Comic collectors say Near Mint.
EXCELLENT
Read once, carefully. A tick or two on the spine.Comic collectors say Very Fine.
VERY GOOD
Spine wear and light creasing. Nothing structural.Somewhere between Fine and Very Good.
GOOD
Creasing, spine roll, tanning. Complete and holding together.
FAIR
Tears, tape or a loose staple. All of it photographed.
POOR
A reading copy, or a filler for a run.
NEAR MINT
Pack fresh. Clean edges, unmarked surface.Near Mint on the card system.
EXCELLENT
A little edge wear, or one mark on the surface.Lightly Played.
VERY GOOD
Whitening, light scratching, or a soft corner.Moderately Played.
GOOD
Obvious wear. Creasing or a bend you can see across the room.Heavily Played.
FAIR
Water, ink, tears or a hard crease.Damaged.
POOR
Damaged enough to be sold as filler, and priced like it.Damaged.
Games have no agreed condition system, so there is nothing to translate. The grade covers the state of the box and the media. What's actually in the box is a separate matter, below.
NEAR MINT
Unmarked. Box square, media clean.
EXCELLENT
Light handling. Box corners just softening.
VERY GOOD
Shelf wear to the box, media clean.
GOOD
Scuffed box, marked media. Everything still works.
FAIR
Heavy wear, a split box, or media that skips.
POOR
Does not run, or it has been got at.
COMPLETENESS IS SEPARATE
A grade is about condition, not contents. Completeness is stated on its own: sealed, complete, or incomplete with the missing parts named. A cartridge in beautiful shape with no box is Near Mint and incomplete, and the listing says both.
Six grades, one system, whatever the thing is. Anything in italics is a translation for people who already grade in another language. It isn't the grade.