noun

1. Biol. an animal, esp. an insect, that transmits a disease-producing organism from a host to a noninfected animal
2. Math.
   1. a mathematical expression denoting a combination of magnitude and direction, as velocity
   2. a directed line segment representing such an expression
   3. an ordered set of real numbers, each denoting a distance on a coordinate axis
3. the particular course followed or to be followed, as by an aircraft; compass heading

Etymology: ModL < L, bearer, carrier < vectus, pp. of vehere, to carry: see way

transitive verb