Variety - a stamp differing in some visible detail from the normal stamp such as a color variation or a minor flaw

Vending and Affixing Machine Perforations - perforations privately applied to imperforate stamps by companies such as the Attleboro Stamp Company, the Brinkerhoff Company, the Farwell Company, the International Vending Machine Co., the Mailometer Co., the Shermack Co., and the U.S. Automatic Vending Co. These privately perforated stamps were sold in coil format for use in vending machines as well as in affixing machines.
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Vending and Machine Perforations Society - the predecessor organization to the Bureau Issues Association and now the United States Stamp Society. There is still a great deal of interest in vending and affixing machine perforations and the USSS does have a web presence, "The Vending and Affixing Machine Perforations Committee".

Vending Booklet - a booklet of stamps intended to be sold from a vending machine

Vending Machine Stamps - stamps produced specifically for use in coin-operated stamp vending machines

Vertical Coil (Endwise Coil) - coil stamps linked together endwise, that is the top of one stamp is connected to the bottom of the next. Note that vertical coils are perforated horizontally.

Vertical Pair, Imperforate Between - a pair of stamps that is fully perforated at the top, sides and bottom, but has no perforations between the stamps

Vertical Pair, Imperforate Horizontally - a pair of stamps that is fully perforated vertically, but has no horizontal perforations 

VF (Very Fine) - a stamp that has all margins clear of the design with one or more sides slightly narrower than the others. "VF" implies that the stamp is well centered, but not perfectly centered.

VG (Very Good) - a stamp that has the perforations or margin on one or more sides touching the design. "VG" implies that the stamp is poorly centered; it is one step below "Fine", or "Just Fine". However, margins or perforations touching the design are the norm for classic nineteenth century stamps, and "VG" does not always imply poor centering in this case, since such centering is normal.

Vignette - the central portion of a stamp design, surrounded by a border or frame. On the early mono-colored stamps the vignette and frame were printed in one pass. In the case of the bi-colored stamp at right, the frame was printed first and then the vignette. 

Vin Fiz Flyer (Rogers Aerial Post) - (Scott CL2) a twenty-five cent black semi-postal U.S. stamp that bore the name of the grape soda made by the Armour Meat Packing Company, who sponsored the coast-to-coast flight in 1911. Only eleven copies are known.

VLH - Very Lightly Hinged