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.