Graphics card = a circuit board that has a processor (usually called a GPU - graphics processing unit), with its own memory and cooling system, that plugs into the computer's motherboard.
If the computer is a laptop, then it might have a graphics card or just the GPU itself. If it does have a graphics card, then it will look like this:
The cooling system has been removed to show the GPU (big chip at the top) and the memory chips (8 blocks surrounding the GPU).
Many laptops and desktop computers don't have a graphics card but do have a GPU. For these computers, the GPU is built into the CPU, so that it is all one chip. It uses the system's memory.
The above picture is a labeled image of an Intel Core i9-10900K CPU. The graphics processor is on the right, labeled GPU.