From this rant:<p>&gt; a matrix represents a linear map between two vector spaces<p>From Wikipedia (<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Matrix_%28mathematics%29" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Matrix_%28mathematics%29</a> ) we see at least two other uses:<p>&gt; A major application of matrices is to represent linear transformations, that is, generalizations of linear functions such as f(x) = 4x. ... Another application of matrices is in the solution of systems of linear equations. ... The adjacency matrix of a finite graph is a basic notion of graph theory. ...