What is "nucleoid"

n. (context microbiology English) The irregularly-shaped region within a prokaryote cell where the genetic material is localized

The nucleoid (meaning nucleus-like) is an irregularly shaped region within the cell of a prokaryote that contains all or most of the genetic material, called genophore. In contrast to the nucleus of a eukaryotic cell, it is not surrounded by a nuclear membrane. The genome of prokaryotic organisms generally is a circular, double-stranded piece of DNA, of which multiple copies may exist at any time. The length of a genome widely varies, but generally is at least a few million base pairs. As in all cellular organisms, length of the DNA molecules of bacterial and archaeal chromosomes is very large compared to the dimensions of the cell, and the genomic DNA molecules must be compacted to fit.