Plasmid and Vector

Plasmid and vector are two types of self-replicative DNA molecules. Plasmids are the extra-chromosomal elements, naturally occurring inside the bacterial cells. Vectors are artificially-introduced DNA molecules into the cells. Plasmid is a double-stranded DNA molecule that acts as a vector. Vector is a DNA molecule that acts as a vehicle in transporting foreign DNA into the host.

https://en.wikipedia.org/wiki/Plasmid