psv uses the first row of a table to identify columns.

In this table, we can refer to the columns by their position (1, 2, 3 & 4) or the name of the values in the first row, e.g. Animal, Color & Avg. Weight.

The first value in the last column of this example is empty, so that column does not have a name and must be referred to by its position (4)

Column names generally do not have any significance for psv, however they can be used for psv commands or via the go API for accessing data in a table.