NTSC is an analog video standard devised by the National Television System Committee from which it gets its name. The NTSC video standard has just less than 30 interlaced frames per second (It is sometimes considered 60fps, but there is a small difference). NTSC video has 525 lines of resolution, although only 482 are used for video. The NTSC format it used in many countries around the world. Notable examples include North America and Japan, as they are the largest camcorder manufacturers.
For more information, see the Wikipedia article on NTSC