An "n-cube" is a geometric shape that extends the concept of a square and a cube to higher dimensions. A 1-cube is a line segment, a 2-cube is a square, and a 3-cube is a regular cube. In general, an n-cube has 2^n vertices, n edges, and is defined in n-dimensional space. The n-cube is also known as a hypercube and is used in various fields, including mathematics, computer science, and physics. It helps in visualizing complex data structures and multidimensional spaces, making it a valuable tool in areas like data analysis and theoretical physics.