Video jargon can quickly get complicated. But the basics of video are comparatively simple and easily learned, and the rest can follow from that.
Slow motion
Slow motion video is created by capturing video at one frame rate and then playing it back and a lower rate. To get smooth video footage it needs a frame rate of 25-30fps, so for a smooth 2x slow motion video, you would need to shoot it at 50-60fps, and for smooth 4x slow motion you'd need to capture at 100-120fps.