A Vector Is Something That Carries
A vector is a quantity with direction, and also an organism that carries disease. Both senses come from the Latin for carrier.
A vector is a quantity with both size and direction, and also an organism that carries a disease from one host to another. The two look unconnected until you translate: Latin *vector* means a carrier, from *vehere*, to carry — the same verb behind *vehicle* and *convey*. A mosquito carries malaria; a mathematical vector carries a point from one place to another.
- A directed quantity. *A velocity vector.*
- A disease carrier. *Mosquitoes are the vector.*
- A course or direction. *On a new vector.*
- Vector graphics — images defined by lines rather than pixels. *A vector logo.*
- Scalar — a quantity with size only. *Speed is a scalar.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | vector | A unit vector. |
| Plural | vectors | Two vectors. |
| Adjective | vectorial | Vectorial analysis. |
| Latin | vehere | To carry. |
| Related | vehicle | A road vehicle. |
- Add the two vectors head to tail.Mathematics.
- Ticks are the vector for the disease.Epidemiology.
- Save the logo as a vector file.Design.
Vector or scalar?
- Scalar — magnitude only: mass, temperature, speed
- Vector — magnitude and direction: velocity, force, displacement
- Speed and velocity are the classic pair: forty miles per hour is a scalar, forty miles per hour north is a vector
- Distance and displacement work the same way
- Adding vectors requires geometry, not just arithmetic
Latin *vector*, a carrier or bearer, from *vehere*, to carry. English used it in astronomy in the 1700s, in mathematics from the 1840s and in epidemiology from around 1900.
Why is a mosquito called a vector?
Because it carries the disease organism between hosts. The Latin word simply means carrier.
What is the difference between speed and velocity?
Speed is a scalar and has size only. Velocity is a vector and includes direction.