Fruity

At cookery class on the weekend the question of what differentiates a fruit and a vegetable came up. I was dead certain of my answer but the mockery made me feel like an idiot and like I was possibly wrong (never!), so here is the official line, several times over:
http://answers.google.com/answers/threadview/id/563886.html
http://www.answerbag.com/q_view/5634

Yessiree Ladies and Gents, the truth is out there, and it is simple. Has seeds? Is fruit. Any other element is a vegetable.