nightcraw1er.488: Well, in that vein of thinking all games are emulated. Whilst dosbox is an emulator, it's more of a backwards compatability system as windows is still built upon dos. Whilst a NES has a totally different architecture and build. So there really needs to be some sort of distinction here, to my mind we are talking about software written for another platform and architecture rather than a comparability fix. For instance to use Ps1 emulator would require both the game rights, and Sony, and the emulator developer, plus possibly other groups to agree for this to happen.
DOSBox is in the same catalog of console emulators. It is not a compatibility layor.
For example, you can run DOSBox on non-x86 machines, like you run NES emulators on x86 machines.
Wine is a compatibility layor.
ScummVM is a set of rewritten game engines.
DOSBox emulate x86 DOS environment and some Windows features. It is an emulator.
Some emulators need original BIOS or ROMs, because there are no free alternatives.
DOSBox do not need non-free parts, because BIOS, VGA BIOS, and other necessary parts already have free and legal alternatives.