Final answer:
In a PowerPoint presentation, fading from one slide to the next is called a transition, which creates a smooth visual flow in the slide show.
Step-by-step explanation:
During an in-service slide show, when each slide fades into view, this effect is known as a transition. In the context of PowerPoint lecture slides, transitions are the visual effects that occur when moving from one slide to the next.
PowerPoint slides typically provide images and descriptions that serve as a foundation for instructors to create their lectures. By using transitions like fade-ins, the visual flow and progression of slides become smoother, which can help in keeping the audience engaged.