auxiliary and vector.

Words

auxiliary = assistant,help,helper,supporter.
vector    = a one dimensional array.

source: http://www.thefreedictionary.com

Application

Vector graphics is the use of geometrical primitives such as points,
lines, curves, and shapes or polygon(s), which are all based on mat
hematical equations, to represent images in computer graphics.Vector
graphics formats are complementary to raster graphics, which is the
representation of images as an array of pixels, as it is typically used for
the representation of photographic images.[1] There are instances when
working with vector tools and formats is the best practice, and instances
when working with raster tools and formats is the best practice. There are
times when both formats come together. An understanding of the adv
antages and limitations of each technology and the relationship between
them is most likely to result in efficient and effective use of tools.

source : http://en.wikipedia.org/wiki/Vector_graphics