What is the difference between a Game Engine and an API?
I read that Game Engine helps in the development of games.
Is OpenGL a game engine? I think it is an API.
Is XNA a game engine?

Moreover, are drivers the *.dll files which interact with the hardware?

You've got a lot of terms mixed up there

API stands for Application Programming Interface, it is an interface a library or program exposes so other libraries or programs can interact with it
When you're writing an application using a certain library you're using its API to get access to its functions

A game engine is a collection of libraries and tools used to build games efficiently; game engines provide an API for programmers to work with

OpenGL is a graphics library which you could use as the base for a rendering system in a game engine, but it is not a game engine in itself
XNA is a library for game-development, but I wouldn't go as far as to actually call it an engine

And no, DLL stands for Dynamic-Link Library, it is a library or part of a library or program which can be loaded in by an application at run-time instead of at compile-time like you see with static libraries

I'd recommend you brush up your general programming knowledge, these kinds of things are rather essential ;)

There's no strict definition of what a game engine is -- it's whatever you say it is.

A game engine might just be an API, or it might be an API and some tools, or an API, some tools, documentation, and sample artwork/content/code...

There's no strict definition of what a game engine is -- it's whatever you say it is.

A game engine might just be an API, or it might be an API and some tools, or an API, some tools, documentation, and sample artwork/content/code...

I know this conversation happens a lot. But are you really going to say that openGL is a game engine just because you feel like calling it that? Its clearly NOT a game engine.. it is a component of a game engine. I dont think its realistic to just say that something is a game engine because you want to call it that. Sure there arent very strict lines between what a game engine is, but its not just anything that you feel like calling one.

No matter how often I feel like calling SDL a game engine, it will not become a game engine. Its a graphics framework... period. It doesnt have to be used for games, nothing about it is specifically geared towards video games.I think its important to realize that there are some basic requirements that must come together to form what we consider a "game engine". a graphics engine is not a game engine... its a graphics engine. A physics engine is not a game engine, its a physics engine.

I do agree that its not always black and white. If you download the Quake source code, you basically have a game engine. At the same time if you download Unity, you also have a game engine... except one with a lot more tools and features. Simply, I think its common sense to consider the MINIMUM components needed to call something a game engine.

But are you really going to say that openGL is a game engine just because you feel like calling it that? Its clearly NOT a game engine..

No.

There's no strict definition of what a game engine is -- it's whatever you say it is.

A game engine might just be an API, or it might be an API and some tools, or an API, some tools, documentation, and sample artwork/content/code...

This is what you said lol. I know I might be poking at it a bit... but youre sayings its WHATEVER you say it is. The fact is... its not WHATEVER you say it is. It does have a context... if it didnt, the term would be meaningless.
Sure it cant be clearly defined... but a game engine is at least made up of some critical components needed in making games, such as input, physics, graphics, etc. All of this stuff will vary depending on the nature of the game.

Yes a game engine can just be an API, but the functions in the API need to be performing these game related tasks. If the functions are simply helping you to draw to the screen, its a graphics engine or framework... not a game engine.

If someone asks be what game engine I use, I tell them none.. because Im using XNA. Im using a game focused framework that makes writing games a bit easier.

[color="#ff0000"]Is XNA a game engine?
[color="#ff0000"]Are drivers the *.dll files which interact with the hardware?

XNA is not a game engine, it's a framework.
DLL files can contain many things, including drivers.

Forget about Game Engine and APIs. Its almost clear now.
Just answer my two questions :-

[color="#ff0000"]Is XNA a game engine?
[color="#ff0000"]Are drivers the *.dll files which interact with the hardware?

Sorry boss. So demanding....