Tossed salad – they are made by tossing ingredients (and usually dressing) in a haphazard way, so that they end up evenly mixed.
Composed salad – these are well, composed. While the ingredients in a tossed salad are thrown together with dressing, the ingredients in a composed salad are carefully assembled from the ground up with a certain structure in mind.
Bound salad – these are held together with a binding agent like mayonnaise or a thick dressing. They look a bit different than traditional composed or tossed salads, as vegetables aren't a requirement. This is a kind of salad you'll often find at traditional picnics or potlucks.