Matrix multiplication is a mathematical operation that takes two matrices and produces a new matrix. To multiply two matrices, the number of columns in the first matrix must equal the number of rows in the second matrix. Each element in the resulting matrix is calculated by taking the dot product of the corresponding row from the first matrix and the column from the second matrix. For example, if you have a 2x3 matrix and a 3x2 matrix, the result will be a 2x2 matrix. This operation is widely used in various fields, including computer science, physics, and economics, to solve systems of equations and perform transformations.