In statistics, a maximum refers to any unique measurement or observation in a data set with the highest value.  

Example:  Find the maximum from the following data:  75,82, 62, 55, 95, 99, 76, 82 and 81.

Step 1)  Put the data in order from least to greatest value. 
                          55, 62, 75, 76, 81, 82, 82, 95, 99

Step 2)  The measurement with the greatest value is the maximum. 
                                                Max = 99