MHXL you most definitely did not make up the term pumpkin axe. It is in the nether star shop labled as such.
The name pumpkin axe was not "made up" by anyone in particular. It was at first used as a generic name amongst those who farmed pumpkins as a eff 5 ubr 3 diamond axe. Then the nether star shop came along and labelled an eff 5 ubr 3 silk 1 axe as a pumpkin axe and soon enough people started using it in trade. People would ask what it was and like an old story it was passed down with lots of variations to the point where any old diamond axe was being called a pumpkin axe.