An English term that's taken from the Old Northern French word gambe, which means "leg." Gammon refers to the upper portion of the pig's hind leg that's cured but not cooked and may or may not be smoked. In the United States this would be called ham, but in England it must be cooked to be ham. Gammon is usually cut into steaks or into rashers that are much thicker than are common in American bacon.
From The Food Lover's Companion, Fourth edition by Sharon Tyler Herbst and Ron Herbst. Copyright © 2007, 2001, 1995, 1990 by Barron's Educational Series, Inc.