This is a French word and refers to a thin strip of food, usually chicken or fish, coated in breadcrumbs and fried. In French the word means 'gudgeon', which means either a small fish often used as bait, or a type of pivot with another object swinging from it. It can also mean a type of pin that holds two pieces of stone together, but it seems more likely that the word in this case refers to the fish (as a goujon is about the size and shape of a very small fish such as whitebait).
The most popular goujons are probably fish fingers, but chicken and other kinds of poultry are often used. The usual method is to dip the strips of meat or fish in beaten egg and then in seasoned breadcrumbs before frying - the egg helps the breadcrumbs to stick.

You can find a nice recipe for chicken goujons here.