Body
The fullness or thickness of a beer on the tongue and palate. Body is part of mouthfeel, which is the tactile sensation beer produces in the mouth. Body is one of the physical qualities of a beer, as is carbonation, and aftertaste (such as astringency and dryness).
Beers may be described as being anywhere from light-bodied to full-bodied:
Light-bodied beers: American Lagers (Budweiser, Coors Light)
Medium-bodied beers: American Porters (Boulevard Bully!)
Full-bodied beers: Imperial Stouts (North Coast Old Rasputin Imperial Stout, Bell's Expedition Stout)