title: What is DataFrame.columns.name?
body: <p>Could you explain to me, what the purpose of the 'DataFrame.columns.name' attribute is? </p>
  
  <p>I unintentionally got it after creating a pivot table and resetting the index. </p>
  
  <pre><code>import pandas as pd
  
  df = pd.DataFrame(['a', 'b'])
  print(df.head())
  
  # OUTPUT:
  #    0
  # 0  a
    1  b
  
  df.columns.name = 'temp'
  print(df.head())
  
  # OUTPUT:
  # temp  0
  # 0     a
  # 1     b
  </code></pre>