Matrix
Also: matrices, weight matrix
An m×n array of numbers. Multiplying an n-dimensional vector by it produces an m-dimensional vector, so a matrix is a linear map; stacking examples as rows also makes a dataset a matrix.
Example
A dense layer with 4 inputs and 3 outputs stores its weights in a 3×4 matrix W; multiplying W by a 4-number input vector gives the layer's 3 pre-activations.