A Noise Function is a mathematical function used to generate random-looking, smooth variations in data. It is commonly used in computer graphics, procedural generation, and simulations to create natural-looking textures, landscapes, and other visual elements. The most popular types of noise functions include Perlin noise and Simplex noise, which help in producing organic patterns that mimic real-world phenomena. These functions work by taking input coordinates and returning a value that varies smoothly across space. This allows for the creation of continuous surfaces, making them ideal for applications like terrain generation in video games or texture mapping in 3D modeling.