Jam is a condiment. It is usually made from pressed fruit, sugar, and sometimes pectin. Jams contains natural sugar as it is made from fruit. Sweetener and other ingredients are often added, we even have some delicious liqueur flavour twists!
A conserve is made of whole fruit cooked in sugar water. Has chunks of fruit in a gelled “background”. A jam is also made of whole fruit cooked in sugar water, but cooked long enough that the fruit pieces are soft enough to spread.
Marmalade is a fruit preserve made from the juice and peel of citrus fruits boiled with sugar and water. The well-known version is made from bitter orange, but it is also made from lemons, limes, grapefruits, mandarins, sweet oranges, bergamots, and other citrus fruits, or a combination.