A tensor is a mathematical object that generalizes scalars, vectors, and matrices. It can be thought of as a multi-dimensional array of numbers that transforms according to specific rules when the coordinate system changes. Tensors are used in various fields, including physics, engineering, and computer science, to represent data and relationships in a structured way. In physics, tensors are essential for describing concepts like stress, strain, and the curvature of space-time in general relativity. They help in formulating physical laws in a way that is independent of the choice of coordinates. This makes tensors a powerful tool for analyzing complex systems.