Definition from Wiktionary, the free dictionary
foreground (plural foregrounds)
- The elements of an image which lie closest to the picture plane.
- The subject of an image, often depicted at the bottom in a two-dimensional work.
- (computing) the application the user is currently interacting with; the application window that appears in front of all others.
Related terms 
The elements of an image which lie closet to the picture plane
- To place in the foreground (physically or metaphorically)