Whats the difference between jelly jam preserves and marmalade?

Jam is made with whole fruit that is cooked down to release the pectin. Jelly is made with fruit juice that pectin is added to. While many canners of today use pectin in jam, it is not traditional. Preserves use the whole fruit without breaking it up, and marmalade uses the zest and pulp, and the juice, however not the whole fruit. The whole fruit would result in a bitter product.

Or more to the point:

• Jelly is made from fruit juice
• Jam is made from pureed fruit
• Preserves are made from whole fruit
• Spreads are made from whole fruit and/or pureed fruit