They are basically the same thing but do different jobs graphic card will help to improve your computer graphics and the Video card allows your computer to use the monitor....these are one your computers speed. Also, because the graphic card is designed only for graphics it processes the graphics better. It also improves the quality of movies and photos on your PC.
Both are same things video card is give normal graphics means you can't play hd videos but graphic card gives you to view better quality pictures,videos you also play hd games (depends on your graphic card series)
but graphic card card is better than video card
Graphics card is called GPU(Graphics processing unit) is specialized hardware add on that helps to improve the Picture and motion on Monitors. It specializes in Floating Point processing and graphics algorithms like ray tracing etc that improves the quality of graphics needed for high-end games, multimedia applications.
Same way sound cards too helps improve the quality of sound such as surround sound. They usually 16 bit.