A graphics card, also known as a video card, is a hardware component that generates output images for display, with key components including the GPU, video BIOS, and RAMDAC. It connects to the motherboard via interfaces such as AGP or PCI-Express and uses various outputs like VGA, HDMI, and DisplayPort to connect to display devices. Additionally, it discusses hardware acceleration, GPGPU, and compares rendering APIs like OpenGL and Direct3D, along with notable vendors in the market.