Zenassem is right. There is not one right definition for a game engine. Some would say that DBP is a game engine, but some would say that it's just a DirectX wrapper in BASIC. When I'm making game engines in DBP and what not I usually make them very high-level, in other words they do a LOT of the work for me. However for this reason, I can only usually use them for like one game and its sequel before I must make a new one. Some people prefer to make them much more flexible so they can use them for several different projects. Also, take note that a game engine is not necessarily just a library of functions or something that you can only use if you're programming; most of the time game engines have tools (such as CryEngine's Sandbox) and sometimes they ARE tools (such as FPS Creator).
To answer your question, actually Blender DOES contain an engine: Blender Game Engine. But BGE does not run Blender, and Blender in itself is not an engine.