In medicine, a vector is a carrier. The best way to understand a vector is to recall its origin as a word. Vector is the Latin word for a "bearer." It is often an intermediary vehicle. For example, in malaria where the mosquito serves as a vector that carries and transfers the infectious agent (Plasmodium) injecting it with a bite. In molecular biology, a vector may be a virus (or a plasmid); a piece of foreign DNA is inserted in the vector genome to be carried and introduced into a recipient (host) cell. In physics, there are vectors but they go beyond the biomedical realm.
Meaning of VECTOR in English
English dictionary of medicine. Английский словарь медицины. 2012