In the world of the Embedded Linux Workshop, an architecture defines a specific application and kernel binary type. For example, if your product is based on an ARM7 without an MMU running in little-endian mode, and you decide to statically link your applications against the uClibc library, your architecture may be named arm7-little-uClibc-static. You can name the architecture anything that makes sense to you. For instance, the architecture that comes with the ELW is named i386 for the Intel 80386 and compatible processors running applications that are dynamically linked with the glibc library.
The actual files created by the ELW. These may be disk images or a series of files to install on a machine.