Day for Night
This is a film term used to describe a shot taken during the day, however, it is meant to take place at night. This is achieved by using filters and underexposing the camera so that the scene seems to take place at night.
This shot is usually taken in the early morning or late afternoon because the shadows the natural light creates are more easily manipulated. A blue filter is typically used because the light it creates is like moonlight.
Most filmmakers try to avoid day for night shots because they can tend to look artificial. They are usually a last resort when time or money is running out.