DJ : Short for dust jacket, a protective and often decorative wrapper, usually made of paper which wraps around the binding of a book.

pub : Common abbreviation for 'published'

VG/VG : Very Good Condition book with a Very Good Condition dust jacket. Very Good Condition indicates a used book that does show some small signs of wear - but no tears - on either binding or paper. Any defects must be noted. (as defined by AB Bookman's Weekly).