S: (n) straight line (a line traced by a point traveling in a constant direction; a line of zero curvature) "the shortest distance between two points is a straight line"
S: (n) vector, transmitter (any agent (person or animal or microorganism) that carries and transmits a disease) "mosquitos are vectors of malaria and yellow fever"; "fleas are vectors of the plague"; "aphids are transmitters of plant diseases"; "when medical scientists talk about vectors they are usually talking about insects"
S: (n) vector ((genetics) a virus or other agent that is used to deliver DNA to a cell)
S: (n) virus ((virology) ultramicroscopic infectious agent that replicates itself only within cells of living hosts; many are pathogenic; a piece of nucleic acid (DNA or RNA) wrapped in a thin coat of protein)