I'm sure there are a ton of theories on this one! The simplest expanation of the origin of the American name of the dish is that the verb "to french" is a cooking term meaning "to cut into thin strings"; hence, they are potatoes that have been frenched, then fried. However, there exist many other theories. By one account, the fried potatoes are called french fries because they are commonly fried in the Belgo-French manner (that is to say frying them twice with a small pause in the middle). Other accounts say that they were once called German fries but the name was changed either for political reasons (Germany was once the enemy of the United States) or simple historical reasons (the traditional theory poses that it was in France during World War I that American soldiers first encountered the dish. However, recent historical evidence indicates that North-American soldiers were actually first served the dish in the Belgian part of the trenches but mistakingly thought they were in France. This makes all together more sense, as fries were and still are the national dish of Belgium, and this also implies that the historically correct name for the dish really should be "Belgian Fries"). A further theory is that the name is a misunderstanding of the archaic British usage of "French fried potatoes" to mean sauted potatoes, i.e. the French way of shallow frying potatoes that have been peeled, parboiled, allowed to cool and then sliced thinly; this is far more convenient than deep frying if frying other items as well, or if using previously prepared materials in a hurry (as in the English cooked breakfast). Reference Link: http://encyclopedia.laborlawtalk.com/French_fries