These standards are from the International Book Collectors Association (IBCA), and the Independent Online Booksellers Association (IOBA). They assume that you are describing both the book and the jacket in a single grade.
Currently most dealers will describe the book and dust jacket separately like this: F/VG – a book in fine condition with a dust jacket in very good condition.
AN/VF/Mint – As New/Very Fine/Mint is to be used only when the book is in the same immaculate condition in which it was published. There can be no defects, no missing pages, no library stamps, etc., and the dustjacket (if it was issued with one) must be perfect, without any tears. (Note: very few “new” books qualify for this grade, as many times there will be rubs/scuffs to the dustjackets from shipping, or bumped lower spine ends/corners from shelving)
F – Fine approaches the condition of As New, but without being crisp. For the use of the term Fine there must also be no defects, etc., and if the jacket has a small tear, or other defect, or looks worn, this should be noted. (The dustjacket may have been slightly rubbed or spine ends slightly bumped from shelving/shipping)
NF – Near Fine is approaching FINE but with a couple of very minor defects or faults
VG – Very Good can describe a used book that does show some small signs of wear – but no tears – on either binding or paper. Any defects must be noted.
G – Good describes the average used and worn book that has all pages or leaves present. Any defects must be noted.
Fair is a worn book that has complete text pages (including those with maps or plates) but may lack endpapers, half-title, etc. (which must be noted). Binding, jacket (if any), etc. may also be worn. All defects must be noted.
Poor/Reading Copy describes a book that is sufficiently worn that its only merit is as a Reading Copy because it does have the complete text, which must be legible. Any missing maps or plates should still be noted. This copy may be soiled, scuffed, stained or spotted and may have loose joints, hinges, pages, etc.
XLib – Ex-library copies must always be designated as such no matter what the condition of the book.
Book Club editions must always be noted as such no matter what the condition of the book.
Binding Copy describes a book in which the pages or leaves are perfect but the binding is very bad, loose, off, or nonexistent.
Dustjacket – in all cases, the lack of a dustjacket should be noted if the book was issued with one.
These terms may be arbitrary, but whatever terms are employed, they may be useless or misleading unless both buyer and seller agree on what they mean in actually describing the book. When in doubt, describe the book exactly as it is, as to physical condition, textual reading, and edition.
Note: The IBCA discourages the practice of elevating a book’s condition from its actual physical appearance based on age. Even if a given old book is in great shape for its age, but its physical condition is still just that, and description of condition should follow the standards given above.