In imaging and photography, each successive stage of reproduction. A copy of an original is first generation; a copy of the copy is second generation, etc.
The term generation is also used to refer to a particular stage or level of technology. For example, the very first phototypesetting machine was a first-generation phototypesetter; the next "version" was the second generation, and so on. In terms of computer software, the term generation is synonymous with version or revision.