Glassine - a woodfree paper. Transparent, glazed and polished on both sides.
Gloss - can refer to the reflectivity of paper itself or to the printed result on it. Gloss of paper is measured by using a gloss meter, which measures reflected light at an angle of 75 and is expressed in gloss units - the higher the number, the glossier the paper surface.
Grain - the direction along which the majority of fibres lie.
Grammage - another expression of gsm or G/m2, used to express weight of paper or board.
Greaseproof - paper free of mechanical pulp, highly resistant to grease. Mainly used for the wrapping of greasy products.
GSM /g/m2 - grammes per square metre. Primary measure of the weight of paper. G/m2 is correct definition by paper makers but GSM is used more frequently by printers.
Green Paper - immature paper which has not been conditioned or had the opportunity to mature naturally.
Grey Board - board made entirely from waste paper. It can be lined and is used for a variety of packaging purposes.