3d engine ??

as you probably see, i'm a newbie in opengl and c++. What is exactly a 3D engine ??????
Is it only a "simple basic opengl window" where we add class and functions like bumpmapping, antialiasing, rotation, scale, and so on ?

Thx for help !!

[Bob]

An engine is a highlevel interface working ontop of another API, like OpenGL or Direct3D, or maybe both, but below the actual gamecode. The engine deals with most stuff concerning level data, rendering, creating window(s), handling sound, and stuff like that.

An engine is not a standalone program, more like a set of helperfunctions.