vector
n. countablen. a way that a disease or virus moves from one person or animal to another. It can also mean a force that has both a size and a specific direction.
n. an organism, typically a biting insect, that transmits a pathogen from one host to another; in physics, a quantity possessing both magnitude and direction.
Mosquitoes are the primary vector for malaria in this region.
Health officials identified the local tick population as the main vector for the recent outbreak of Lyme disease.
The engineer calculated the wind velocity as a vector to determine how much the aircraft would drift off its intended flight path during the storm.
Learned borrowing from Latin vector (“carrier, transporter”), from vehō (“to carry, transport, bear”), also ultimately the root of English vehicle. The “person or entity that passes along an urban legend or other meme” sense derives from the disease sense. The mathematics sense was coined by Irish mathematician and astronomer William Rowan Hamilton in 1846.
In biological contexts, it refers to the carrier of a disease; in mathematics and physics, it refers to a directed quantity.