A Key Frame (also written as Keyframe) is a drawing or position in animation that defines a critical point in motion, representing the start, end, or significant moments within an action sequence. In traditional animation, key frames are drawn by senior animators while in-between frames are completed by assistants, establishing the fundamental structure and timing of animated movement.

Key frames define the poses, positions, and critical moments that give animation its character and intent. They represent extremes of motion, moments of impact, anticipation poses before major actions, and resolution points after movements complete. The spacing between key frames determines the speed and feel of motion, with close spacing creating slow movement and wide spacing producing fast action. In digital animation and video editing, keyframes also define points where parameters like position, scale, opacity, or effects change, with software interpolating values between them.

In AI video generation, key frames can be used to guide generation by specifying images that the video should pass through at specific points in time. This frames-to-video approach gives creators control over critical visual moments while allowing the AI to generate the motion that connects them, combining the precision of keyframe-based workflows with the efficiency of AI synthesis.