Juxtaposition

 Juxtaposition mean side-by-side position.

juxta·po·sition·al adj.jux·ta·po·si·tion   (jkst-p-zshn)
[French] juxtaposer : Latin ixt, close by; see yeug- in Indo-European roots + French poser, to place (from Old French; seepose¹).]

The result of juxtaposition is contrasting two colors, and an act of  position is to be close together.

Noun1: locating, positioning, emplacement, location, placement, position -   the act of the juxtaposition is putting something in a certain place.Noun2: position, place - the particular portion of space occupied by something.

People will attracting by two difference elements. It mark-making a contrast shading to controlled an area, or the area is making very softly handled just like concepts or imagery. 

Examples:In Meret Oppenhiem's 1936 Le dejeuner en fourrure- 'Luncheon in Fur', the perplexing juxtaposition of fur and teacup unsettles the viewer, as we question form and function, and wonder about the answer to Picasso's quip that 'anything could be covered in fur'.

http://drawsketch.about.com/od/drawingglossary/g/juxtaposition.htm

Understanding Juxtaposition in photography. 
Basically it mean the relationship between two subject in a photo so that each of the subject will be more attract the another.

The reflections (another feature highly valued in photography) are juxtaposed within the mirror like walls of the building. A good one

The two penquins are juxtaposed in the water, capturing one from above and to the side and the other from below and underneath giving a 360 degree view, clever

Here the Church is juxtaposed beside a tall contrasting blue building

rather amusing, don't you think? It makes you think about just how the legs hang there. A bit of irony

Delightful, and I would not normally have thought of this as juxtaposition. But it is

Bizarre juxtaposition, but it serves its purpos

juxtaposition allows the assessment in the overall achitecture of the city



The natural juxtaposition of the reflections in the windows of the building has been seized on by the photography, who had recognized the symbolic nature of the technique in his travels
http://www.photographytips.com.au/living-under-a-bridge-and-juxtaposition/