(vek’tər) noun. vektor. 1. In mathematics and physics, a variable that has both distance and direction. Compare scalar. 2. In computer graphics, a line drawn in a certain direction from a starting point to an endpoint, both of whose locations are identified by the computer using x-y-coordinates on a grid. Vectors are used in some graphics programs instead of groups of dots (on paper) or pixels (on screen). See also vector graphics. 3. In data structures, a one-dimensional array—a set of items arranged in a single column or row.