It is always a good idea to label or identify your data, so your worksheet can be understood by who ever uses it. It would be extremely difficult to make sense of multiple rows and columns of unidentified numerical data. We use labels so we can understand the meaning of the rows and columns of data. Basically a label is a simple text description of the data it represents.

If your worksheet contains information about the age, height, and weight of a group of people; the words age, height, and weight, would make ideal labels for the data.