viewport

noun

1. A viewing window.

   “acrylic plastic viewports in pressure vessels for human occupancy”

2. A typically rectangular region representing the range or area currently visible (within a window, screen, etc.).

   “Dragging the scroll-bar changes which part of the picture is visible within the viewport.”

verb

1. (transitive)To clip (an image or region) so that it fits in a viewport.

   “Some general ideas on clipping, viewporting, and windowing can be found in Rogers and Adams.”

   “Viewporting is an operation that takes the portion of the picture that has been mapped into the square region delimited by -1,+1,-1,+1 and further maps it into a rectangular subregion of the screen (a viewport).”

   “The main thing I want you to take away from this chapter is knowing where to start and creating a very simple viewported web site using nothing more than an extra <meta> tag and simple HTML.”