Jelly is a type of food made by cooking fruit juice with sugar until it resembles a soft, elastic spread. Jam is a type of food made by cooking mashed, crushed, or chopped fruit with sugar until it resembles a loose spread.
Jam has a semi-firm consistency, and the cooked-down fruit lends it a chunkier texture. Jelly has a firmer consistency than jam and is uniform in texture.
Jelly is more translucent than jam.
Jam is gelled syrup that can't hold itself in its place. Jelly is clear and sparkling and holds itself in its place.
Both jams and jellies are used as food accompaniments with a variety of food such as bread, cake, and other bakery items.