Cross tabulation is when you take information about a group of things and organize it into a table. Imagine you have a bunch of different colored toys (like red, blue, and yellow balls) and you want to know how many of each kind you have. You could make a table with one row for each color and one column for how many of each color you have. Then you would count up how many of each color you have and put the numbers in the right box in the table.
Cross tabulation can also be used to compare two different kinds of information. For example, imagine you have a list of animals (like lions, giraffes, and monkeys) and you want to know how many of each live in a certain area and how many are male or female. You could make a table with one row for each type of animal (like lions) and one column for how many are male and how many are female. Then you would count up how many lions there are, and put the numbers in the right box for male or female. You could do the same thing for the other kinds of animals in the list.