At school, I was taught that a rain forest is tropical like a jungle (as opposed to a forest, which is not) but it is defined the the layers of canapes: ground growers, mid-growers, and the light-seeking trees at the top when looking up in a rain forest.
So, a quick note to British people watching "I'm a Celebrity...", Australia DOES NOT actually have jungles: they're rainforests!
This is up on my list of annoyances with "mentalist" being used for "crazy" and "pressurised" being used for "pressured". GAH!!!
...oooh, I feel better now...