What is a matrix in biology?

According to Biology Online, a matrix in biology is the ground substance where things fill a space. An example of this is the space found within the mitochondrion.

The main usage of a matrix is for the loose mesh work inside where cells become embedded like an extracellular matrix. In addition, the matrix can be utilized as a absorbent material or a filter. In tissues, most of the cells in the tissue are surrounded with extracellular matrixes. These matrixes contain proteins like fibronectin, laminin and collagen. The extracellular matrix performs the role of regulating functions in the cells. The proteins in extracellular matrix bind to cell surface types of receptors and integrins.