What is linearised plasmid?

Plasmids are extrachromosomal genetic materials present in bacteria. They ar circular in shape. But in case of several genetic engineering experiments, these plasmids are made linear, by cutting them in one particular site. This cutting is done using special enzymes called restriction endonucleases. When the plasmid is cut at one site using this enzyme, it loses its circular shape and becomes linear. Such a plasmid is called linear or linearised plasmid.