When building a gaming PC, you will come across the terms "GPU" and "graphics card" - often used interchangeably. So is a GPU a graphics card? The answer is a little bit of yes and a little bit of no.
A GPU or graphics processing unit, is in a basic sense, a CPU that only carries out graphics related tasks. A graphics card on the other hand is essentially a GPU plus the components that make it a workable component of your gaming PC. The graphics card comes with things like coolers, their own RAM and connnectors to the motherboard. The easiest way to put it is that GPU does all "work" - it creates the graphics. The graphics card is the GPU plus the components that make it allow it to be part of a gaming PC build.
Why Is It Important to Know the Difference?
From a building your PC standpoint, it is important to know the difference because of price considerations. In most PC builds you will buy a graphics card and a CPU. Together these parts will usually run between $400 and $1,000 depending on high end your system is. However, for those on tight budgets it is possible to buy an APU which combines the CPU and GPU into one chip. Recall what we say in the paragraph above, a graphics card comes with its own RAM and VRAM, meaning it doesn't use your system's CPU. An APU however is a GPU that taps into the processing power of the CPU. In one chip you have both components. APUs are usually far cheaper than the combined price of the graphics card and CPU.
GPUs and Laptop Gaming
If you game on a laptop you cannot have a graphics card. Instead, your laptop has a GPU within it which will process the graphics for your computer. Usually this GPU will also borrow RAM from your laptop's CPU. This usually does not lend to receiving the highest end graphics on a laptop. A good alternative is an external GPU which is actually a bit of a misnomer. An external GPU is actually a casing where you can put a graphics card to increase the graphic potential of your laptop while gaming.
Should You Buy a GPU or Graphics Card?
As we say above, the answer to this question depends on what you need for your PC. If you are building a gaming PC and you don't want an APU - the combination of the GPU or CPU - then you need a graphics card. You are looking for something like a GTX 1080 (high end) or GTX 970 (lower end). If you laptop game, consider an external GPU to house a graphics card.