One of the ways to indicate something is bigger is adding ón to a word. It does make something BIGGER

          libro    ---> book
          librón         large book

          hombre       man
          hombrón     big, strong man

          grande        big
          grandón      REALLY REALLY big

El médico es un hombrón.
      The doctor is a big man.
El bebé tiene un manchurrón en el babero.
      The baby has a big stain on his bib.
Para barrer las hojas secas, lo mejor es un
        escobón.
      To sweep dry leaves, the best thing to use is a
        big broom.

We use ona for feminine nouns or adjectives.

¡Ay que canción mas dulzona!
      Oh, what a big, sweet song!
La enfermera es una mujerona
      The nurse is a big woman.