1. (n.) Same as Radius vector.

2. (n.) A directed quantity, as a straight line, a force, or a velocity. Vectors are said to be equal when their directions are the same their magnitudes equal. Cf. Scalar.

aerial infection air line airborne infection axis azimuth beeline biological vector carrier chord communicability compass bearing compass direction contagion contagiousness contamination course cryptogenic infection diagonal diameter direct infection direct line directrix droplet infection dust infection edge epidemiology great-circle course hand infection heading indirect infection infection infectiousness lee side magnetic bearing mechanical vector normal perpendicular phytogenic infection primary infection pyogenic infection radius radius vector relative bearing right line secant secondary infection segment shortcut side straight straight course straight line straight stretch straightaway streamline subclinical infection tack taint tangent transversal true bearing vehicle virus waterborne infection weather side zoogenic infection