The term "vector" has different definitions in science, primarily depending whether the topic is math/physical science or medicine/biology.
Vector Definition in Math and Physics
In physical science and engineering, a vector is a geometric object which has both magnitude or length and direction. A vector is commonly represented by a line segment in a specific direction, indicated by an arrow. Vectors are typically used to describe physical quantities which have a directional quality in addition to a quantity that could be described by a single number with a unit.
Also Known As: Euclidean vector, spatial vector, geometric vector, mathematical vector
Examples: Velocity and force are vector quantities. In contrast, speed and distance are scalar quantities, which have magnitude but not direction.
Vector Definition in Biology and Medicine
In the biological sciences, the term vector refers to an organism that transmits a disease, parasite, or genetic information from one species to another.
Examples: Mosquitoes are a vector of malaria. A virus may be used as a vector to insert genes into a bacterial cell.