a region in the cells of prokaryotes that contains nucleic acids but which is not bounded by a membrane: it is analogous in function to the nucleus of eukaryotic cells
See nucleoid in American Heritage Dictionary 4
(no͞oˈklē-oidˌ, nyo͞oˈ-)
noun
The part of a bacterium or virus that contains nucleic acid and is analogous in function to the nucleus of a eukaryotic cell.