4K 60p is a video resolution and frame rate that refers to a 4K resolution output at 60 frames per second.
4K refers to the resolution, while 60p refers to the frame rate.
Explanation
4K
A generic term for any resolution with a horizontal pixel count of about 4,000. 4K UHD (Ultra High Definition) is a specific 4K resolution with a resolution of 3840 x 2160 pixels.
60p
A frame rate that indicates the number of individual frames in each second of video. 60p is a progressive video format, which means that the entire video frame is displayed simultaneously.
Frame rate
The number of frames per second in a video. The most common frame rates are 24, 25, 30, and 60 frames per second.
4K 60p is the maximum frame rate that some Ultra HD Blu-ray players and 4K media streamers can output.