A data matrix is like a big table full of information. Imagine that you had 100 people, and each person had 10 different pieces of information about them. You could put all of that information in a data matrix. It would be like a table with 100 rows, one for each person. And each row would have 10 columns, one for each bit of information about that particular person. A data matrix is a way to organize lots of data in a way that's easy for computers to understand and use.