Defininition 3) above is closest to what I would call a real world silhouette, as in made in real life with real 3d objects.

So, it could be the outline of a ship at sea against the brightness of the sky behind it, or really any other situation whereby a figure or object is placed in front of a backround that is substantially brighter than itself.

I would knock out a quick render to illustrate, but I am about to jump on a plane and head off to do a gig and will be away from Poser for three weeks.

Ditto in reference to the striping on the poser square, but you try lighting it directly and rendering it and you'll soon a situation where it'll look ghastly! :)