What is the difference between a Jam and a Jelly?

The title is pretty self explanatory so I'm going to just dive in.

According to Dictionary.com :

jam: n. a preserve of whole fruit, slightly crushed, boiled with sugar.

jelly: n. a food preparation of a soft, elastic consistency due to the presence of gelatin, pectin, etc, esp. fruit juice boiled down with sugar and used as a sweet spread.

I would like to point out at this time that "jam" had twelve dictionary results whereas "jelly" had merely five.

wiseGEEK.com provides us with further analysis:

Jam is made from whole fruit and jelly is made from fruit juices. Jam is healthier for you. Jelly is generally sweeter than jam. Both are types of fruit preserves; other fruit preserves include confit, fruit butter, conserves, and marmalade.

Now you know.